Replaced all calls to fragmentPosition() with sk_FragCoord

BUG=skia:

Change-Id: I179576e148ea6caf6e1c40f0a216421898bcb35d
Reviewed-on: https://skia-review.googlesource.com/5941
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/GrProgramDesc.cpp b/src/gpu/GrProgramDesc.cpp
index 87a4a27..080ba5e 100644
--- a/src/gpu/GrProgramDesc.cpp
+++ b/src/gpu/GrProgramDesc.cpp
@@ -195,14 +195,9 @@
     // make sure any padding in the header is zeroed.
     memset(header, 0, kHeaderSize);
 
-    GrRenderTarget* rt = pipeline.getRenderTarget();
+    header->fSurfaceOriginKey = 0;
 
-    if (requiredFeatures & (GrProcessor::kFragmentPosition_RequiredFeature |
-                            GrProcessor::kSampleLocations_RequiredFeature)) {
-        header->fSurfaceOriginKey = GrGLSLFragmentShaderBuilder::KeyForSurfaceOrigin(rt->origin());
-    } else {
-        header->fSurfaceOriginKey = 0;
-    }
+    GrRenderTarget* rt = pipeline.getRenderTarget();
 
     if (requiredFeatures & GrProcessor::kSampleLocations_RequiredFeature) {
         SkASSERT(pipeline.isHWAntialiasState());
diff --git a/src/gpu/GrProgramDesc.h b/src/gpu/GrProgramDesc.h
index 2a26f2d..a20cdfc 100644
--- a/src/gpu/GrProgramDesc.h
+++ b/src/gpu/GrProgramDesc.h
@@ -12,6 +12,7 @@
 #include "GrTypesPriv.h"
 #include "SkOpts.h"
 #include "SkTArray.h"
+#include "glsl/GrGLSLFragmentShaderBuilder.h"
 
 class GrShaderCaps;
 class GrPipeline;
@@ -80,6 +81,11 @@
         return !(*this == other);
     }
 
+    void setSurfaceOriginKey(int key) {
+        KeyHeader* header = this->atOffset<KeyHeader, kHeaderOffset>();
+        header->fSurfaceOriginKey = key;
+    }
+
     static bool Less(const GrProgramDesc& a, const GrProgramDesc& b) {
         SkASSERT(SkIsAlign4(a.keyLength()));
         int l = a.keyLength() >> 2;
diff --git a/src/gpu/GrXferProcessor.cpp b/src/gpu/GrXferProcessor.cpp
index c2a16b8..7de0d77 100644
--- a/src/gpu/GrXferProcessor.cpp
+++ b/src/gpu/GrXferProcessor.cpp
@@ -27,7 +27,6 @@
         fDstTexture.reset(dstTexture->texture());
         fDstTextureOffset = dstTexture->offset();
         this->addTextureSampler(&fDstTexture);
-        this->setWillReadFragmentPosition();
     }
 }
 
diff --git a/src/gpu/effects/GrConvexPolyEffect.cpp b/src/gpu/effects/GrConvexPolyEffect.cpp
index a64e5cb..65ed87b 100644
--- a/src/gpu/effects/GrConvexPolyEffect.cpp
+++ b/src/gpu/effects/GrConvexPolyEffect.cpp
@@ -34,7 +34,6 @@
     AARectEffect(GrPrimitiveEdgeType edgeType, const SkRect& rect)
         : fRect(rect), fEdgeType(edgeType) {
         this->initClassID<AARectEffect>();
-        this->setWillReadFragmentPosition();
     }
 
     GrGLSLFragmentProcessor* onCreateGLSLInstance() const override;
@@ -113,24 +112,27 @@
                                                     &rectName);
 
     GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
-    const char* fragmentPos = fragBuilder->fragmentPosition();
     if (GrProcessorEdgeTypeIsAA(aare.getEdgeType())) {
         // The amount of coverage removed in x and y by the edges is computed as a pair of negative
         // numbers, xSub and ySub.
         fragBuilder->codeAppend("\t\tfloat xSub, ySub;\n");
-        fragBuilder->codeAppendf("\t\txSub = min(%s.x - %s.x, 0.0);\n", fragmentPos, rectName);
-        fragBuilder->codeAppendf("\t\txSub += min(%s.z - %s.x, 0.0);\n", rectName, fragmentPos);
-        fragBuilder->codeAppendf("\t\tySub = min(%s.y - %s.y, 0.0);\n", fragmentPos, rectName);
-        fragBuilder->codeAppendf("\t\tySub += min(%s.w - %s.y, 0.0);\n", rectName, fragmentPos);
+        fragBuilder->codeAppendf("\t\txSub = min(sk_FragCoord.x - %s.x, 0.0);\n", rectName);
+        fragBuilder->codeAppendf("\t\txSub += min(%s.z - sk_FragCoord.x, 0.0);\n", rectName);
+        fragBuilder->codeAppendf("\t\tySub = min(sk_FragCoord.y - %s.y, 0.0);\n", rectName);
+        fragBuilder->codeAppendf("\t\tySub += min(%s.w - sk_FragCoord.y, 0.0);\n", rectName);
         // Now compute coverage in x and y and multiply them to get the fraction of the pixel
         // covered.
         fragBuilder->codeAppendf("\t\tfloat alpha = (1.0 + max(xSub, -1.0)) * (1.0 + max(ySub, -1.0));\n");
     } else {
         fragBuilder->codeAppendf("\t\tfloat alpha = 1.0;\n");
-        fragBuilder->codeAppendf("\t\talpha *= (%s.x - %s.x) > -0.5 ? 1.0 : 0.0;\n", fragmentPos, rectName);
-        fragBuilder->codeAppendf("\t\talpha *= (%s.z - %s.x) > -0.5 ? 1.0 : 0.0;\n", rectName, fragmentPos);
-        fragBuilder->codeAppendf("\t\talpha *= (%s.y - %s.y) > -0.5 ? 1.0 : 0.0;\n", fragmentPos, rectName);
-        fragBuilder->codeAppendf("\t\talpha *= (%s.w - %s.y) > -0.5 ? 1.0 : 0.0;\n", rectName, fragmentPos);
+        fragBuilder->codeAppendf("\t\talpha *= (sk_FragCoord.x - %s.x) > -0.5 ? 1.0 : 0.0;\n",
+                                 rectName);
+        fragBuilder->codeAppendf("\t\talpha *= (%s.z - sk_FragCoord.x) > -0.5 ? 1.0 : 0.0;\n",
+                                 rectName);
+        fragBuilder->codeAppendf("\t\talpha *= (sk_FragCoord.y - %s.y) > -0.5 ? 1.0 : 0.0;\n",
+                                 rectName);
+        fragBuilder->codeAppendf("\t\talpha *= (%s.w - sk_FragCoord.y) > -0.5 ? 1.0 : 0.0;\n",
+                                 rectName);
     }
 
     if (GrProcessorEdgeTypeIsInverseFill(aare.getEdgeType())) {
@@ -199,10 +201,10 @@
     GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
     fragBuilder->codeAppend("\t\tfloat alpha = 1.0;\n");
     fragBuilder->codeAppend("\t\tfloat edge;\n");
-    const char* fragmentPos = fragBuilder->fragmentPosition();
     for (int i = 0; i < cpe.getEdgeCount(); ++i) {
-        fragBuilder->codeAppendf("\t\tedge = dot(%s[%d], vec3(%s.x, %s.y, 1));\n",
-                                 edgeArrayName, i, fragmentPos, fragmentPos);
+        fragBuilder->codeAppendf("\t\tedge = dot(%s[%d], vec3(sk_FragCoord.x, sk_FragCoord.y, "
+                                                             "1));\n",
+                                 edgeArrayName, i);
         if (GrProcessorEdgeTypeIsAA(cpe.getEdgeType())) {
             fragBuilder->codeAppend("\t\tedge = clamp(edge, 0.0, 1.0);\n");
         } else {
@@ -348,7 +350,6 @@
     for (int i = 0; i < n; ++i) {
         fEdges[3 * i + 2] += SK_ScalarHalf;
     }
-    this->setWillReadFragmentPosition();
 }
 
 bool GrConvexPolyEffect::onIsEqual(const GrFragmentProcessor& other) const {
diff --git a/src/gpu/effects/GrDitherEffect.cpp b/src/gpu/effects/GrDitherEffect.cpp
index eb7fe62..a93e74f 100644
--- a/src/gpu/effects/GrDitherEffect.cpp
+++ b/src/gpu/effects/GrDitherEffect.cpp
@@ -28,7 +28,6 @@
 private:
     DitherEffect() {
         this->initClassID<DitherEffect>();
-        this->setWillReadFragmentPosition();
     }
 
     GrGLSLFragmentProcessor* onCreateGLSLInstance() const override;
@@ -79,8 +78,8 @@
     // For each channel c, add the random offset to the pixel to either bump
     // it up or let it remain constant during quantization.
     fragBuilder->codeAppendf("\t\tfloat r = "
-                             "fract(sin(dot(%s.xy ,vec2(12.9898,78.233))) * 43758.5453);\n",
-                             fragBuilder->fragmentPosition());
+                             "fract(sin(dot(sk_FragCoord.xy, vec2(12.9898,78.233))) * "
+                                                            "43758.5453);\n");
     fragBuilder->codeAppendf("\t\t%s = (1.0/255.0) * vec4(r, r, r, r) + %s;\n",
                              args.fOutputColor, GrGLSLExpr4(args.fInputColor).c_str());
 }
diff --git a/src/gpu/effects/GrOvalEffect.cpp b/src/gpu/effects/GrOvalEffect.cpp
index 13cbd25..21a4ba0 100644
--- a/src/gpu/effects/GrOvalEffect.cpp
+++ b/src/gpu/effects/GrOvalEffect.cpp
@@ -68,7 +68,6 @@
     , fRadius(r)
     , fEdgeType(edgeType) {
     this->initClassID<CircleEffect>();
-    this->setWillReadFragmentPosition();
 }
 
 bool CircleEffect::onIsEqual(const GrFragmentProcessor& other) const {
@@ -124,7 +123,6 @@
                                                       &circleName);
 
     GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
-    const char* fragmentPos = fragBuilder->fragmentPosition();
 
     SkASSERT(kHairlineAA_GrProcessorEdgeType != ce.getEdgeType());
     // TODO: Right now the distance to circle caclulation is performed in a space normalized to the
@@ -132,11 +130,13 @@
     // mediump. It'd be nice to only to this on mediump devices but we currently don't have the
     // caps here.
     if (GrProcessorEdgeTypeIsInverseFill(ce.getEdgeType())) {
-        fragBuilder->codeAppendf("float d = (length((%s.xy - %s.xy) * %s.w) - 1.0) * %s.z;",
-                                 circleName, fragmentPos, circleName, circleName);
+        fragBuilder->codeAppendf("float d = (length((%s.xy - sk_FragCoord.xy) * %s.w) - 1.0) * "
+                                            "%s.z;",
+                                 circleName, circleName, circleName);
     } else {
-        fragBuilder->codeAppendf("float d = (1.0 - length((%s.xy - %s.xy) *  %s.w)) * %s.z;",
-                                 circleName, fragmentPos, circleName, circleName);
+        fragBuilder->codeAppendf("float d = (1.0 - length((%s.xy - sk_FragCoord.xy) *  %s.w)) * "
+                                                  "%s.z;",
+                                 circleName, circleName, circleName);
     }
     if (GrProcessorEdgeTypeIsAA(ce.getEdgeType())) {
         fragBuilder->codeAppend("d = clamp(d, 0.0, 1.0);");
@@ -235,7 +235,6 @@
     , fRadii(SkVector::Make(rx, ry))
     , fEdgeType(edgeType) {
     this->initClassID<EllipseEffect>();
-    this->setWillReadFragmentPosition();
 }
 
 bool EllipseEffect::onIsEqual(const GrFragmentProcessor& other) const {
@@ -305,10 +304,9 @@
     }
 
     GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
-    const char* fragmentPos = fragBuilder->fragmentPosition();
 
     // d is the offset to the ellipse center
-    fragBuilder->codeAppendf("vec2 d = %s.xy - %s.xy;", fragmentPos, ellipseName);
+    fragBuilder->codeAppendf("vec2 d = sk_FragCoord.xy - %s.xy;", ellipseName);
     if (scaleName) {
         fragBuilder->codeAppendf("d *= %s.y;", scaleName);
     }
diff --git a/src/gpu/effects/GrRRectEffect.cpp b/src/gpu/effects/GrRRectEffect.cpp
index 4db3957..adebc24 100644
--- a/src/gpu/effects/GrRRectEffect.cpp
+++ b/src/gpu/effects/GrRRectEffect.cpp
@@ -99,7 +99,6 @@
     , fEdgeType(edgeType)
     , fCircularCornerFlags(circularCornerFlags) {
     this->initClassID<CircularRRectEffect>();
-    this->setWillReadFragmentPosition();
 }
 
 bool CircularRRectEffect::onIsEqual(const GrFragmentProcessor& other) const {
@@ -178,7 +177,6 @@
     }
 
     GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
-    const char* fragmentPos = fragBuilder->fragmentPosition();
     // At each quarter-circle corner we compute a vector that is the offset of the fragment position
     // from the circle center. The vector is pinned in x and y to be in the quarter-plane relevant
     // to that corner. This means that points near the interior near the rrect top edge will have
@@ -196,84 +194,86 @@
     // alphas together.
     switch (crre.getCircularCornerFlags()) {
         case CircularRRectEffect::kAll_CornerFlags:
-            fragBuilder->codeAppendf("vec2 dxy0 = %s.xy - %s.xy;", rectName, fragmentPos);
-            fragBuilder->codeAppendf("vec2 dxy1 = %s.xy - %s.zw;", fragmentPos, rectName);
+            fragBuilder->codeAppendf("vec2 dxy0 = %s.xy - sk_FragCoord.xy;", rectName);
+            fragBuilder->codeAppendf("vec2 dxy1 = sk_FragCoord.xy - %s.zw;", rectName);
             fragBuilder->codeAppend("vec2 dxy = max(max(dxy0, dxy1), 0.0);");
             fragBuilder->codeAppendf("float alpha = %s;", clampedCircleDistance.c_str());
             break;
         case CircularRRectEffect::kTopLeft_CornerFlag:
-            fragBuilder->codeAppendf("vec2 dxy = max(%s.xy - %s.xy, 0.0);",
-                                     rectName, fragmentPos);
-            fragBuilder->codeAppendf("float rightAlpha = clamp(%s.z - %s.x, 0.0, 1.0);",
-                                     rectName, fragmentPos);
-            fragBuilder->codeAppendf("float bottomAlpha = clamp(%s.w - %s.y, 0.0, 1.0);",
-                                     rectName, fragmentPos);
+            fragBuilder->codeAppendf("vec2 dxy = max(%s.xy - sk_FragCoord.xy, 0.0);",
+                                     rectName);
+            fragBuilder->codeAppendf("float rightAlpha = clamp(%s.z - sk_FragCoord.x, 0.0, 1.0);",
+                                     rectName);
+            fragBuilder->codeAppendf("float bottomAlpha = clamp(%s.w - sk_FragCoord.y, 0.0, 1.0);",
+                                     rectName);
             fragBuilder->codeAppendf("float alpha = bottomAlpha * rightAlpha * %s;",
                                      clampedCircleDistance.c_str());
             break;
         case CircularRRectEffect::kTopRight_CornerFlag:
-            fragBuilder->codeAppendf("vec2 dxy = max(vec2(%s.x - %s.z, %s.y - %s.y), 0.0);",
-                                     fragmentPos, rectName, rectName, fragmentPos);
-            fragBuilder->codeAppendf("float leftAlpha = clamp(%s.x - %s.x, 0.0, 1.0);",
-                                     fragmentPos, rectName);
-            fragBuilder->codeAppendf("float bottomAlpha = clamp(%s.w - %s.y, 0.0, 1.0);",
-                                     rectName, fragmentPos);
+            fragBuilder->codeAppendf("vec2 dxy = max(vec2(sk_FragCoord.x - %s.z, "
+                                                         "%s.y - sk_FragCoord.y), 0.0);",
+                                     rectName, rectName);
+            fragBuilder->codeAppendf("float leftAlpha = clamp(sk_FragCoord.x - %s.x, 0.0, 1.0);",
+                                     rectName);
+            fragBuilder->codeAppendf("float bottomAlpha = clamp(%s.w - sk_FragCoord.y, 0.0, 1.0);",
+                                     rectName);
             fragBuilder->codeAppendf("float alpha = bottomAlpha * leftAlpha * %s;",
                                      clampedCircleDistance.c_str());
             break;
         case CircularRRectEffect::kBottomRight_CornerFlag:
-            fragBuilder->codeAppendf("vec2 dxy = max(%s.xy - %s.zw, 0.0);",
-                                     fragmentPos, rectName);
-            fragBuilder->codeAppendf("float leftAlpha = clamp(%s.x - %s.x, 0.0, 1.0);",
-                                     fragmentPos, rectName);
-            fragBuilder->codeAppendf("float topAlpha = clamp(%s.y - %s.y, 0.0, 1.0);",
-                                     fragmentPos, rectName);
+            fragBuilder->codeAppendf("vec2 dxy = max(sk_FragCoord.xy - %s.zw, 0.0);",
+                                     rectName);
+            fragBuilder->codeAppendf("float leftAlpha = clamp(sk_FragCoord.x - %s.x, 0.0, 1.0);",
+                                     rectName);
+            fragBuilder->codeAppendf("float topAlpha = clamp(sk_FragCoord.y - %s.y, 0.0, 1.0);",
+                                     rectName);
             fragBuilder->codeAppendf("float alpha = topAlpha * leftAlpha * %s;",
                                      clampedCircleDistance.c_str());
             break;
         case CircularRRectEffect::kBottomLeft_CornerFlag:
-            fragBuilder->codeAppendf("vec2 dxy = max(vec2(%s.x - %s.x, %s.y - %s.w), 0.0);",
-                                     rectName, fragmentPos, fragmentPos, rectName);
-            fragBuilder->codeAppendf("float rightAlpha = clamp(%s.z - %s.x, 0.0, 1.0);",
-                                     rectName, fragmentPos);
-            fragBuilder->codeAppendf("float topAlpha = clamp(%s.y - %s.y, 0.0, 1.0);",
-                                     fragmentPos, rectName);
+            fragBuilder->codeAppendf("vec2 dxy = max(vec2(%s.x - sk_FragCoord.x, sk_FragCoord.y - "
+                                     "%s.w), 0.0);",
+                                     rectName, rectName);
+            fragBuilder->codeAppendf("float rightAlpha = clamp(%s.z - sk_FragCoord.x, 0.0, 1.0);",
+                                     rectName);
+            fragBuilder->codeAppendf("float topAlpha = clamp(sk_FragCoord.y - %s.y, 0.0, 1.0);",
+                                     rectName);
             fragBuilder->codeAppendf("float alpha = topAlpha * rightAlpha * %s;",
                                      clampedCircleDistance.c_str());
             break;
         case CircularRRectEffect::kLeft_CornerFlags:
-            fragBuilder->codeAppendf("vec2 dxy0 = %s.xy - %s.xy;", rectName, fragmentPos);
-            fragBuilder->codeAppendf("float dy1 = %s.y - %s.w;", fragmentPos, rectName);
+            fragBuilder->codeAppendf("vec2 dxy0 = %s.xy - sk_FragCoord.xy;", rectName);
+            fragBuilder->codeAppendf("float dy1 = sk_FragCoord.y - %s.w;", rectName);
             fragBuilder->codeAppend("vec2 dxy = max(vec2(dxy0.x, max(dxy0.y, dy1)), 0.0);");
-            fragBuilder->codeAppendf("float rightAlpha = clamp(%s.z - %s.x, 0.0, 1.0);",
-                                     rectName, fragmentPos);
+            fragBuilder->codeAppendf("float rightAlpha = clamp(%s.z - sk_FragCoord.x, 0.0, 1.0);",
+                                     rectName);
             fragBuilder->codeAppendf("float alpha = rightAlpha * %s;",
                                      clampedCircleDistance.c_str());
             break;
         case CircularRRectEffect::kTop_CornerFlags:
-            fragBuilder->codeAppendf("vec2 dxy0 = %s.xy - %s.xy;", rectName, fragmentPos);
-            fragBuilder->codeAppendf("float dx1 = %s.x - %s.z;", fragmentPos, rectName);
+            fragBuilder->codeAppendf("vec2 dxy0 = %s.xy - sk_FragCoord.xy;", rectName);
+            fragBuilder->codeAppendf("float dx1 = sk_FragCoord.x - %s.z;", rectName);
             fragBuilder->codeAppend("vec2 dxy = max(vec2(max(dxy0.x, dx1), dxy0.y), 0.0);");
-            fragBuilder->codeAppendf("float bottomAlpha = clamp(%s.w - %s.y, 0.0, 1.0);",
-                                     rectName, fragmentPos);
+            fragBuilder->codeAppendf("float bottomAlpha = clamp(%s.w - sk_FragCoord.y, 0.0, 1.0);",
+                                     rectName);
             fragBuilder->codeAppendf("float alpha = bottomAlpha * %s;",
                                      clampedCircleDistance.c_str());
             break;
         case CircularRRectEffect::kRight_CornerFlags:
-            fragBuilder->codeAppendf("float dy0 = %s.y - %s.y;", rectName, fragmentPos);
-            fragBuilder->codeAppendf("vec2 dxy1 = %s.xy - %s.zw;", fragmentPos, rectName);
+            fragBuilder->codeAppendf("float dy0 = %s.y - sk_FragCoord.y;", rectName);
+            fragBuilder->codeAppendf("vec2 dxy1 = sk_FragCoord.xy - %s.zw;", rectName);
             fragBuilder->codeAppend("vec2 dxy = max(vec2(dxy1.x, max(dy0, dxy1.y)), 0.0);");
-            fragBuilder->codeAppendf("float leftAlpha = clamp(%s.x - %s.x, 0.0, 1.0);",
-                                     fragmentPos, rectName);
+            fragBuilder->codeAppendf("float leftAlpha = clamp(sk_FragCoord.x - %s.x, 0.0, 1.0);",
+                                     rectName);
             fragBuilder->codeAppendf("float alpha = leftAlpha * %s;",
                                      clampedCircleDistance.c_str());
             break;
         case CircularRRectEffect::kBottom_CornerFlags:
-            fragBuilder->codeAppendf("float dx0 = %s.x - %s.x;", rectName, fragmentPos);
-            fragBuilder->codeAppendf("vec2 dxy1 = %s.xy - %s.zw;", fragmentPos, rectName);
+            fragBuilder->codeAppendf("float dx0 = %s.x - sk_FragCoord.x;", rectName);
+            fragBuilder->codeAppendf("vec2 dxy1 = sk_FragCoord.xy - %s.zw;", rectName);
             fragBuilder->codeAppend("vec2 dxy = max(vec2(max(dx0, dxy1.x), dxy1.y), 0.0);");
-            fragBuilder->codeAppendf("float topAlpha = clamp(%s.y - %s.y, 0.0, 1.0);",
-                                     fragmentPos, rectName);
+            fragBuilder->codeAppendf("float topAlpha = clamp(sk_FragCoord.y - %s.y, 0.0, 1.0);",
+                                     rectName);
             fragBuilder->codeAppendf("float alpha = topAlpha * %s;",
                                      clampedCircleDistance.c_str());
             break;
@@ -434,7 +434,6 @@
     : fRRect(rrect)
     , fEdgeType(edgeType) {
     this->initClassID<EllipticalRRectEffect>();
-    this->setWillReadFragmentPosition();
 }
 
 bool EllipticalRRectEffect::onIsEqual(const GrFragmentProcessor& other) const {
@@ -516,7 +515,6 @@
                                                    &rectName);
 
     GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
-    const char* fragmentPos = fragBuilder->fragmentPosition();
     // At each quarter-ellipse corner we compute a vector that is the offset of the fragment pos
     // to the ellipse center. The vector is pinned in x and y to be in the quarter-plane relevant
     // to that corner. This means that points near the interior near the rrect top edge will have
@@ -529,8 +527,8 @@
     // The code below is a simplified version of the above that performs maxs on the vector
     // components before computing distances and alpha values so that only one distance computation
     // need be computed to determine the min alpha.
-    fragBuilder->codeAppendf("vec2 dxy0 = %s.xy - %s.xy;", rectName, fragmentPos);
-    fragBuilder->codeAppendf("vec2 dxy1 = %s.xy - %s.zw;", fragmentPos, rectName);
+    fragBuilder->codeAppendf("vec2 dxy0 = %s.xy - sk_FragCoord.xy;", rectName);
+    fragBuilder->codeAppendf("vec2 dxy1 = sk_FragCoord.xy - %s.zw;", rectName);
 
     // If we're on a device with a "real" mediump then we'll do the distance computation in a space
     // that is normalized by the largest radius. The scale uniform will be scale, 1/scale. The
diff --git a/src/gpu/effects/GrTextureDomain.cpp b/src/gpu/effects/GrTextureDomain.cpp
index d6872e1..095f100 100644
--- a/src/gpu/effects/GrTextureDomain.cpp
+++ b/src/gpu/effects/GrTextureDomain.cpp
@@ -330,7 +330,6 @@
     fDeviceSpaceOffset.fX = deviceSpaceOffset.fX - subset.fLeft;
     fDeviceSpaceOffset.fY = deviceSpaceOffset.fY - subset.fTop;
     this->initClassID<GrDeviceSpaceTextureDecalFragmentProcessor>();
-    this->setWillReadFragmentPosition();
 }
 
 GrGLSLFragmentProcessor* GrDeviceSpaceTextureDecalFragmentProcessor::onCreateGLSLInstance() const  {
@@ -345,8 +344,7 @@
                                                                      kDefault_GrSLPrecision,
                                                                      "scaleAndTranslate",
                                                                      &scaleAndTranslateName);
-            args.fFragBuilder->codeAppendf("vec2 coords = %s.xy * %s.xy + %s.zw;",
-                                           args.fFragBuilder->fragmentPosition(),
+            args.fFragBuilder->codeAppendf("vec2 coords = sk_FragCoord.xy * %s.xy + %s.zw;",
                                            scaleAndTranslateName, scaleAndTranslateName);
             fGLDomain.sampleTexture(args.fFragBuilder,
                                     args.fUniformHandler,
diff --git a/src/gpu/gl/GrGLGpuProgramCache.cpp b/src/gpu/gl/GrGLGpuProgramCache.cpp
index c1ca160..2ff5dc7 100644
--- a/src/gpu/gl/GrGLGpuProgramCache.cpp
+++ b/src/gpu/gl/GrGLGpuProgramCache.cpp
@@ -81,11 +81,18 @@
     desc.finalize();
     std::unique_ptr<Entry>* entry = fMap.find(desc);
     if (!entry) {
+        // Didn't find an origin-independent version, check with the specific origin
+        GrSurfaceOrigin origin = pipeline.getRenderTarget()->origin();
+        desc.setSurfaceOriginKey(GrGLSLFragmentShaderBuilder::KeyForSurfaceOrigin(origin));
+        desc.finalize();
+        entry = fMap.find(desc);
+    }
+    if (!entry) {
         // We have a cache miss
 #ifdef PROGRAM_CACHE_STATS
         ++fCacheMisses;
 #endif
-        GrGLProgram* program = GrGLProgramBuilder::CreateProgram(pipeline, primProc, desc, fGpu);
+        GrGLProgram* program = GrGLProgramBuilder::CreateProgram(pipeline, primProc, &desc, fGpu);
         if (nullptr == program) {
             return nullptr;
         }
diff --git a/src/gpu/gl/builders/GrGLProgramBuilder.cpp b/src/gpu/gl/builders/GrGLProgramBuilder.cpp
index c3e81fb..f3548e6 100644
--- a/src/gpu/gl/builders/GrGLProgramBuilder.cpp
+++ b/src/gpu/gl/builders/GrGLProgramBuilder.cpp
@@ -30,7 +30,7 @@
 
 GrGLProgram* GrGLProgramBuilder::CreateProgram(const GrPipeline& pipeline,
                                                const GrPrimitiveProcessor& primProc,
-                                               const GrProgramDesc& desc,
+                                               GrProgramDesc* desc,
                                                GrGLGpu* gpu) {
     GrAutoLocaleSetter als("C");
 
@@ -56,7 +56,7 @@
 GrGLProgramBuilder::GrGLProgramBuilder(GrGLGpu* gpu,
                                        const GrPipeline& pipeline,
                                        const GrPrimitiveProcessor& primProc,
-                                       const GrProgramDesc& desc)
+                                       GrProgramDesc* desc)
     : INHERITED(pipeline, primProc, desc)
     , fGpu(gpu)
     , fVaryingHandler(this)
@@ -89,6 +89,13 @@
     }
 
     *shaderIds->append() = shaderId;
+    if (!outInputs->fFlipY) {
+        GrProgramDesc* d = this->desc();
+        // the program doesn't care about the surface origin, set the key to zero to indicate that
+        // it doesn't matter
+        d->setSurfaceOriginKey(0);
+        d->finalize();
+    }
 
     return true;
 }
@@ -244,7 +251,7 @@
 
 GrGLProgram* GrGLProgramBuilder::createProgram(GrGLuint programID) {
     return new GrGLProgram(fGpu,
-                           this->desc(),
+                           *this->desc(),
                            fUniformHandles,
                            programID,
                            fUniformHandler.fUniforms,
diff --git a/src/gpu/gl/builders/GrGLProgramBuilder.h b/src/gpu/gl/builders/GrGLProgramBuilder.h
index 84d6d91..cfbb734 100644
--- a/src/gpu/gl/builders/GrGLProgramBuilder.h
+++ b/src/gpu/gl/builders/GrGLProgramBuilder.h
@@ -29,11 +29,14 @@
      * The program implements what is specified in the stages given as input.
      * After successful generation, the builder result objects are available
      * to be used.
+     * This function may modify the GrProgramDesc by setting the surface origin
+     * key to 0 (unspecified) if it turns out the program does not care about
+     * the surface origin.
      * @return true if generation was successful.
      */
     static GrGLProgram* CreateProgram(const GrPipeline&,
                                       const GrPrimitiveProcessor&,
-                                      const GrProgramDesc&,
+                                      GrProgramDesc*,
                                       GrGLGpu*);
 
     const GrCaps* caps() const override;
@@ -42,7 +45,7 @@
 
 private:
     GrGLProgramBuilder(GrGLGpu*, const GrPipeline&, const GrPrimitiveProcessor&,
-                       const GrProgramDesc&);
+                       GrProgramDesc*);
 
     bool compileAndAttachShaders(GrGLSLShaderBuilder& shader,
                                  GrGLuint programId,
diff --git a/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp b/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp
index 7ef7348..f583420 100644
--- a/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp
+++ b/src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp
@@ -130,11 +130,6 @@
     return coords2D;
 }
 
-const char* GrGLSLFragmentShaderBuilder::fragmentPosition() {
-    SkDEBUGCODE(fUsedProcessorFeatures |= GrProcessor::kFragmentPosition_RequiredFeature;)
-    return "sk_FragCoord";
-}
-
 const char* GrGLSLFragmentShaderBuilder::distanceVectorName() const {
     return "fsDistanceVector";
 }
diff --git a/src/gpu/glsl/GrGLSLFragmentShaderBuilder.h b/src/gpu/glsl/GrGLSLFragmentShaderBuilder.h
index f7d2323..ab806ea 100644
--- a/src/gpu/glsl/GrGLSLFragmentShaderBuilder.h
+++ b/src/gpu/glsl/GrGLSLFragmentShaderBuilder.h
@@ -47,11 +47,6 @@
      */
     virtual SkString ensureCoords2D(const GrShaderVar&) = 0;
 
-
-    /** Returns a variable name that represents the position of the fragment in the FS. The position
-        is in device space (e.g. 0,0 is the top left and pixel centers are at half-integers). */
-    virtual const char* fragmentPosition() = 0;
-
     // TODO: remove this method.
     void declAppendf(const char* fmt, ...);
 
@@ -167,7 +162,6 @@
     // Shared GrGLSLFragmentBuilder interface.
     bool enableFeature(GLSLFeature) override;
     virtual SkString ensureCoords2D(const GrShaderVar&) override;
-    const char* fragmentPosition() override;
     const char* distanceVectorName() const override;
 
     // GrGLSLFPFragmentBuilder interface.
diff --git a/src/gpu/glsl/GrGLSLProgramBuilder.cpp b/src/gpu/glsl/GrGLSLProgramBuilder.cpp
index c805825..2b8a3a7 100644
--- a/src/gpu/glsl/GrGLSLProgramBuilder.cpp
+++ b/src/gpu/glsl/GrGLSLProgramBuilder.cpp
@@ -20,7 +20,7 @@
 
 GrGLSLProgramBuilder::GrGLSLProgramBuilder(const GrPipeline& pipeline,
                                            const GrPrimitiveProcessor& primProc,
-                                           const GrProgramDesc& desc)
+                                           GrProgramDesc* desc)
     : fVS(this)
     , fGS(this)
     , fFS(this)
@@ -348,7 +348,7 @@
 void GrGLSLProgramBuilder::emitFSOutputSwizzle(bool hasSecondaryOutput) {
     // Swizzle the fragment shader outputs if necessary.
     GrSwizzle swizzle;
-    swizzle.setFromKey(this->desc().header().fOutputSwizzle);
+    swizzle.setFromKey(this->desc()->header().fOutputSwizzle);
     if (swizzle != GrSwizzle::RGBA()) {
         fFS.codeAppendf("%s = %s.%s;", fFS.getPrimaryColorOutputName(),
                         fFS.getPrimaryColorOutputName(),
diff --git a/src/gpu/glsl/GrGLSLProgramBuilder.h b/src/gpu/glsl/GrGLSLProgramBuilder.h
index 2dba90f..3074110 100644
--- a/src/gpu/glsl/GrGLSLProgramBuilder.h
+++ b/src/gpu/glsl/GrGLSLProgramBuilder.h
@@ -40,8 +40,8 @@
 
     const GrPrimitiveProcessor& primitiveProcessor() const { return fPrimProc; }
     const GrPipeline& pipeline() const { return fPipeline; }
-    const GrProgramDesc& desc() const { return fDesc; }
-    const GrProgramDesc::KeyHeader& header() const { return fDesc.header(); }
+    GrProgramDesc* desc() { return fDesc; }
+    const GrProgramDesc::KeyHeader& header() const { return fDesc->header(); }
 
     void appendUniformDecls(GrShaderFlags visibility, SkString*) const;
 
@@ -99,7 +99,7 @@
 
     const GrPipeline&           fPipeline;
     const GrPrimitiveProcessor& fPrimProc;
-    const GrProgramDesc&        fDesc;
+    GrProgramDesc*              fDesc;
 
     BuiltinUniformHandles fUniformHandles;
 
@@ -110,7 +110,7 @@
 protected:
     explicit GrGLSLProgramBuilder(const GrPipeline&,
                                   const GrPrimitiveProcessor&,
-                                  const GrProgramDesc&);
+                                  GrProgramDesc*);
 
     void addFeature(GrShaderFlags shaders, uint32_t featureBit, const char* extensionName);
 
diff --git a/src/gpu/glsl/GrGLSLVertexShaderBuilder.cpp b/src/gpu/glsl/GrGLSLVertexShaderBuilder.cpp
index f8302b3..2aded89 100644
--- a/src/gpu/glsl/GrGLSLVertexShaderBuilder.cpp
+++ b/src/gpu/glsl/GrGLSLVertexShaderBuilder.cpp
@@ -22,7 +22,7 @@
     fProgramBuilder->addRTAdjustmentUniform(kHigh_GrSLPrecision,
                                             fProgramBuilder->rtAdjustment(),
                                             &fRtAdjustName);
-    if (this->getProgramBuilder()->desc().header().fSnapVerticesToPixelCenters) {
+    if (this->getProgramBuilder()->desc()->header().fSnapVerticesToPixelCenters) {
         if (kVec3f_GrSLType == posVar.getType()) {
             const char* p = posVar.c_str();
             this->codeAppendf("{vec2 _posTmp = vec2(%s.x/%s.z, %s.y/%s.z);", p, p, p, p);
@@ -47,7 +47,7 @@
     }
     // We could have the GrGeometryProcessor do this, but its just easier to have it performed
     // here. If we ever need to set variable pointsize, then we can reinvestigate.
-    if (this->getProgramBuilder()->desc().header().fHasPointSize) {
+    if (this->getProgramBuilder()->desc()->header().fHasPointSize) {
         this->codeAppend("gl_PointSize = 1.0;");
     }
 }
diff --git a/src/gpu/glsl/GrGLSLXferProcessor.cpp b/src/gpu/glsl/GrGLSLXferProcessor.cpp
index e269819..4101080 100644
--- a/src/gpu/glsl/GrGLSLXferProcessor.cpp
+++ b/src/gpu/glsl/GrGLSLXferProcessor.cpp
@@ -49,11 +49,10 @@
                                                   kDefault_GrSLPrecision,
                                                   "DstTextureCoordScale",
                                                   &dstCoordScaleName);
-        const char* fragPos = fragBuilder->fragmentPosition();
 
         fragBuilder->codeAppend("// Read color from copy of the destination.\n");
-        fragBuilder->codeAppendf("vec2 _dstTexCoord = (%s.xy - %s) * %s;",
-                                 fragPos, dstTopLeftName, dstCoordScaleName);
+        fragBuilder->codeAppendf("vec2 _dstTexCoord = (sk_FragCoord.xy - %s) * %s;",
+                                 dstTopLeftName, dstCoordScaleName);
 
         if (!topDown) {
             fragBuilder->codeAppend("_dstTexCoord.y = 1.0 - _dstTexCoord.y;");
diff --git a/src/gpu/ops/GrDrawOp.h b/src/gpu/ops/GrDrawOp.h
index 9e949b1..447a4dd 100644
--- a/src/gpu/ops/GrDrawOp.h
+++ b/src/gpu/ops/GrDrawOp.h
@@ -64,9 +64,6 @@
 
     bool installPipeline(const GrPipeline::CreateArgs&);
 
-    // TODO no GrPrimitiveProcessors yet read fragment position
-    bool willReadFragmentPosition() const { return false; }
-
 protected:
     static SkString DumpPipelineInfo(const GrPipeline& pipeline) {
         SkString string;
diff --git a/src/gpu/ops/GrPLSPathRenderer.cpp b/src/gpu/ops/GrPLSPathRenderer.cpp
index 545d12b..384733f 100644
--- a/src/gpu/ops/GrPLSPathRenderer.cpp
+++ b/src/gpu/ops/GrPLSPathRenderer.cpp
@@ -344,8 +344,7 @@
             // gl_FragCoord. The oriented box positioning of the subsamples is of course not
             // optimal, but it greatly simplifies the math and this simplification is necessary for
             // performance reasons.
-            fsBuilder->codeAppendf("highp vec2 firstSample = %s.xy - vec2(0.25);",
-                                   fsBuilder->fragmentPosition());
+            fsBuilder->codeAppendf("highp vec2 firstSample = sk_FragCoord.xy - vec2(0.25);");
             fsBuilder->codeAppendf("highp vec2 delta1 = %s;", delta1.fsIn());
             fsBuilder->codeAppendf("highp vec2 delta2 = %s;", delta2.fsIn());
             fsBuilder->codeAppendf("highp vec2 delta3 = %s;", delta3.fsIn());
@@ -423,7 +422,6 @@
                                             kHigh_GrSLPrecision);
         fInWindings = &this->addVertexAttrib("inWindings", kInt_GrVertexAttribType,
                                              kLow_GrSLPrecision);
-        this->setWillReadFragmentPosition();
     }
 
     const Attribute* fInPosition;
@@ -542,8 +540,7 @@
             fsBuilder->codeAppend("highp vec2 uvIncY = uvdX * 0.1 + uvdY * 0.55;");
             fsBuilder->codeAppendf("highp vec2 uv = %s.xy - uvdX * 0.35 - uvdY * 0.25;",
                                    uv.fsIn());
-            fsBuilder->codeAppendf("highp vec2 firstSample = %s.xy - vec2(0.25);",
-                                   fsBuilder->fragmentPosition());
+            fsBuilder->codeAppendf("highp vec2 firstSample = sk_FragCoord.xy - vec2(0.25);");
             fsBuilder->codeAppendf("highp float d = dot(%s, (firstSample - %s).yx) * 2.0;",
                                    delta.fsIn(), ep1.fsIn());
             fsBuilder->codeAppendf("pls.windings[0] += %s(d, uv) ? %s : 0;", inQuadName.c_str(),
@@ -604,7 +601,6 @@
                                               kHigh_GrSLPrecision);
         fInWindings  = &this->addVertexAttrib("inWindings", kInt_GrVertexAttribType,
                                               kLow_GrSLPrecision);
-        this->setWillReadFragmentPosition();
     }
 
     const Attribute* fInPosition;
diff --git a/src/gpu/vk/GrVkPipelineStateBuilder.cpp b/src/gpu/vk/GrVkPipelineStateBuilder.cpp
index 4125938..f7a6173 100644
--- a/src/gpu/vk/GrVkPipelineStateBuilder.cpp
+++ b/src/gpu/vk/GrVkPipelineStateBuilder.cpp
@@ -19,7 +19,7 @@
                                                                const GrStencilSettings& stencil,
                                                                const GrPrimitiveProcessor& primProc,
                                                                GrPrimitiveType primitiveType,
-                                                               const GrVkPipelineState::Desc& desc,
+                                                               GrVkPipelineState::Desc* desc,
                                                                const GrVkRenderPass& renderPass) {
     // create a builder.  This will be handed off to effects so they can use it to add
     // uniforms, varyings, textures, etc
@@ -39,7 +39,7 @@
 GrVkPipelineStateBuilder::GrVkPipelineStateBuilder(GrVkGpu* gpu,
                                                    const GrPipeline& pipeline,
                                                    const GrPrimitiveProcessor& primProc,
-                                                   const GrProgramDesc& desc)
+                                                   GrProgramDesc* desc)
     : INHERITED(pipeline, primProc, desc)
     , fGpu(gpu)
     , fVaryingHandler(this)
@@ -62,7 +62,8 @@
                                                     const GrGLSLShaderBuilder& builder,
                                                     VkShaderModule* shaderModule,
                                                     VkPipelineShaderStageCreateInfo* stageInfo,
-                                                    const SkSL::Program::Settings& settings) {
+                                                    const SkSL::Program::Settings& settings,
+                                                    GrVkPipelineState::Desc* desc) {
     SkString shaderString;
     for (int i = 0; i < builder.fCompilerStrings.count(); ++i) {
         if (builder.fCompilerStrings[i]) {
@@ -80,13 +81,19 @@
     if (inputs.fRTHeight) {
         this->addRTHeightUniform(SKSL_RTHEIGHT_NAME);
     }
+    if (!inputs.fFlipY) {
+        // the program doesn't care about the surface origin, set the key to zero to indicate that
+        // it doesn't matter
+        desc->setSurfaceOriginKey(0);
+        desc->finalize();
+    }
     return result;
 }
 
 GrVkPipelineState* GrVkPipelineStateBuilder::finalize(const GrStencilSettings& stencil,
                                                       GrPrimitiveType primitiveType,
                                                       const GrVkRenderPass& renderPass,
-                                                      const GrVkPipelineState::Desc& desc) {
+                                                      GrVkPipelineState::Desc* desc) {
     VkDescriptorSetLayout dsLayout[2];
     VkPipelineLayout pipelineLayout;
     VkShaderModule vertShaderModule;
@@ -133,7 +140,8 @@
                                               fVS,
                                               &vertShaderModule,
                                               &shaderStageInfo[0],
-                                              settings));
+                                              settings,
+                                              desc));
 
     // TODO: geometry shader support.
     SkASSERT(!this->primitiveProcessor().willUseGeoShader());
@@ -142,7 +150,8 @@
                                               fFS,
                                               &fragShaderModule,
                                               &shaderStageInfo[1],
-                                              settings));
+                                              settings,
+                                              desc));
 
     GrVkPipeline* pipeline = resourceProvider.createPipeline(fPipeline,
                                                              stencil,
@@ -165,7 +174,7 @@
     }
 
     return new GrVkPipelineState(fGpu,
-                                 desc,
+                                 *desc,
                                  pipeline,
                                  pipelineLayout,
                                  samplerDSHandle,
diff --git a/src/gpu/vk/GrVkPipelineStateBuilder.h b/src/gpu/vk/GrVkPipelineStateBuilder.h
index cf4a983..ae59ec4 100644
--- a/src/gpu/vk/GrVkPipelineStateBuilder.h
+++ b/src/gpu/vk/GrVkPipelineStateBuilder.h
@@ -28,6 +28,8 @@
     *
     * The GrVkPipelineState implements what is specified in the GrPipeline and GrPrimitiveProcessor
     * as input. After successful generation, the builder result objects are available to be used.
+    * This function may modify the program key by setting the surface origin key to 0 (unspecified)
+    * if it turns out the program does not care about the surface origin.
     * @return true if generation was successful.
     */
     static GrVkPipelineState* CreatePipelineState(GrVkGpu*,
@@ -35,7 +37,7 @@
                                                   const GrStencilSettings&,
                                                   const GrPrimitiveProcessor&,
                                                   GrPrimitiveType,
-                                                  const GrVkPipelineState::Desc&,
+                                                  GrVkPipelineState::Desc*,
                                                   const GrVkRenderPass& renderPass);
 
     const GrCaps* caps() const override;
@@ -49,18 +51,19 @@
     GrVkPipelineStateBuilder(GrVkGpu*,
                              const GrPipeline&,
                              const GrPrimitiveProcessor&,
-                             const GrProgramDesc&);
+                             GrProgramDesc*);
 
     GrVkPipelineState* finalize(const GrStencilSettings&,
                                 GrPrimitiveType primitiveType,
                                 const GrVkRenderPass& renderPass,
-                                const GrVkPipelineState::Desc&);
+                                GrVkPipelineState::Desc*);
 
     bool createVkShaderModule(VkShaderStageFlagBits stage,
                               const GrGLSLShaderBuilder& builder,
                               VkShaderModule* shaderModule,
                               VkPipelineShaderStageCreateInfo* stageInfo,
-                              const SkSL::Program::Settings& settings);
+                              const SkSL::Program::Settings& settings,
+                              GrVkPipelineState::Desc* desc);
 
     GrGLSLUniformHandler* uniformHandler() override { return &fUniformHandler; }
     const GrGLSLUniformHandler* uniformHandler() const override { return &fUniformHandler; }
diff --git a/src/gpu/vk/GrVkPipelineStateCache.cpp b/src/gpu/vk/GrVkPipelineStateCache.cpp
index 7b935eb..f8d77a9 100644
--- a/src/gpu/vk/GrVkPipelineStateCache.cpp
+++ b/src/gpu/vk/GrVkPipelineStateCache.cpp
@@ -101,6 +101,13 @@
 
     std::unique_ptr<Entry>* entry = fMap.find(desc);
     if (!entry) {
+        // Didn't find an origin-independent version, check with the specific origin
+        GrSurfaceOrigin origin = pipeline.getRenderTarget()->origin();
+        desc.setSurfaceOriginKey(GrGLSLFragmentShaderBuilder::KeyForSurfaceOrigin(origin));
+        desc.finalize();
+        entry = fMap.find(desc);
+    }
+    if (!entry) {
 #ifdef GR_PIPELINE_STATE_CACHE_STATS
         ++fCacheMisses;
 #endif
@@ -110,7 +117,7 @@
                                                           stencil,
                                                           primProc,
                                                           primitiveType,
-                                                          desc,
+                                                          &desc,
                                                           renderPass));
         if (nullptr == pipelineState) {
             return nullptr;