Revert "Switched highp float to highfloat and mediump float to half."

This reverts commit 88d99c63878c2d3d340120f0321676f72afcb4f0.

Reason for revert: Believed to be causing unit test failures in Chrome roll:

https://build.chromium.org/p/tryserver.chromium.android/builders/linux_android_rel_ng/builds/364433
https://luci-logdog.appspot.com/v/?s=chromium%2Fbb%2Ftryserver.chromium.android%2Flinux_android_rel_ng%2F364433%2F%2B%2Frecipes%2Fsteps%2Fcontent_browsertests__with_patch__on_Android%2F0%2Flogs%2FWebRtcCaptureFromElementBrowserTest.VerifyCanvasWebGLCaptureColor%2F0

Original change's description:
> Switched highp float to highfloat and mediump float to half.
> 
> The ultimate goal is to end up with "float" and "half", but this
> intermediate step uses "highfloat" so that it is clear if I missed a
> "float" somewhere. Once this lands, a subsequent CL will switch all
> "highfloats" back to "floats".
> 
> Bug: skia:
> Change-Id: Ia13225c7a0a0a2901e07665891c473d2500ddcca
> Reviewed-on: https://skia-review.googlesource.com/31000
> Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
> Reviewed-by: Brian Salomon <bsalomon@google.com>

TBR=bsalomon@google.com,csmartdalton@google.com,ethannicholas@google.com

Change-Id: I8bfa97547ac3920d433665f161d27df3f15c83aa
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/35705
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
diff --git a/src/shaders/gradients/SkGradientShader.cpp b/src/shaders/gradients/SkGradientShader.cpp
index ea3affb..1b24ef9 100644
--- a/src/shaders/gradients/SkGradientShader.cpp
+++ b/src/shaders/gradients/SkGradientShader.cpp
@@ -1361,15 +1361,17 @@
                                                    const GrGradientEffect& ge) {
     if (int colorCount = color_type_to_color_count(ge.getColorType())) {
         fColorsUni = uniformHandler->addUniformArray(kFragment_GrShaderFlag,
-                                                     kHalf4_GrSLType,
+                                                     kVec4f_GrSLType,
+                                                     kDefault_GrSLPrecision,
                                                      "Colors",
                                                      colorCount);
         if (ge.fColorType == kSingleHardStop_ColorType) {
-            fHardStopT = uniformHandler->addUniform(kFragment_GrShaderFlag, kHalf_GrSLType,
-                                                    "HardStopT");
+            fHardStopT = uniformHandler->addUniform(kFragment_GrShaderFlag, kFloat_GrSLType,
+                                                    kDefault_GrSLPrecision, "HardStopT");
         }
     } else {
-        fFSYUni = uniformHandler->addUniform(kFragment_GrShaderFlag, kHalf_GrSLType,
+        fFSYUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
+                                             kFloat_GrSLType, kDefault_GrSLPrecision,
                                              "GradientYCoordFS");
     }
 }
@@ -1552,14 +1554,14 @@
     // First, apply tiling rules.
     switch (ge.fTileMode) {
     case SkShader::kClamp_TileMode:
-        fragBuilder->codeAppendf("half clamp_t = clamp(%s, 0.0, 1.0);", t);
+        fragBuilder->codeAppendf("float clamp_t = clamp(%s, 0.0, 1.0);", t);
         break;
     case SkShader::kRepeat_TileMode:
-        fragBuilder->codeAppendf("half clamp_t = fract(%s);", t);
+        fragBuilder->codeAppendf("float clamp_t = fract(%s);", t);
         break;
     case SkShader::kMirror_TileMode:
-        fragBuilder->codeAppendf("half t_1 = %s - 1.0;", t);
-        fragBuilder->codeAppendf("half clamp_t = abs(t_1 - 2.0 * floor(t_1 * 0.5) - 1.0);");
+        fragBuilder->codeAppendf("float t_1 = %s - 1.0;", t);
+        fragBuilder->codeAppendf("float clamp_t = abs(t_1 - 2.0 * floor(t_1 * 0.5) - 1.0);");
         break;
     }
 
@@ -1569,8 +1571,8 @@
         case kSingleHardStop_ColorType: {
             const char* stopT = uniformHandler->getUniformCStr(fHardStopT);
 
-            fragBuilder->codeAppend ("half4 start, end;");
-            fragBuilder->codeAppend ("half relative_t;");
+            fragBuilder->codeAppend ("float4 start, end;");
+            fragBuilder->codeAppend ("float relative_t;");
             fragBuilder->codeAppendf("if (clamp_t < %s) {", stopT);
             fragBuilder->codeAppendf("    start = %s[0];", colors);
             fragBuilder->codeAppendf("    end   = %s[1];", colors);
@@ -1580,13 +1582,13 @@
             fragBuilder->codeAppendf("    end   = %s[3];", colors);
             fragBuilder->codeAppendf("    relative_t = (clamp_t - %s) / (1 - %s);", stopT, stopT);
             fragBuilder->codeAppend ("}");
-            fragBuilder->codeAppend ("half4 colorTemp = mix(start, end, relative_t);");
+            fragBuilder->codeAppend ("float4 colorTemp = mix(start, end, relative_t);");
 
             break;
         }
 
         case kHardStopLeftEdged_ColorType: {
-            fragBuilder->codeAppendf("half4 colorTemp = mix(%s[1], %s[2], clamp_t);", colors,
+            fragBuilder->codeAppendf("float4 colorTemp = mix(%s[1], %s[2], clamp_t);", colors,
                                      colors);
             if (SkShader::kClamp_TileMode == ge.fTileMode) {
                 fragBuilder->codeAppendf("if (%s < 0.0) {", t);
@@ -1598,7 +1600,7 @@
         }
 
         case kHardStopRightEdged_ColorType: {
-            fragBuilder->codeAppendf("half4 colorTemp = mix(%s[0], %s[1], clamp_t);", colors,
+            fragBuilder->codeAppendf("float4 colorTemp = mix(%s[0], %s[1], clamp_t);", colors,
                                      colors);
             if (SkShader::kClamp_TileMode == ge.fTileMode) {
                 fragBuilder->codeAppendf("if (%s > 1.0) {", t);
@@ -1610,15 +1612,15 @@
         }
 
         case kTwo_ColorType: {
-            fragBuilder->codeAppendf("half4 colorTemp = mix(%s[0], %s[1], clamp_t);",
+            fragBuilder->codeAppendf("float4 colorTemp = mix(%s[0], %s[1], clamp_t);",
                                      colors, colors);
 
             break;
         }
 
         case kThree_ColorType: {
-            fragBuilder->codeAppendf("half oneMinus2t = 1.0 - (2.0 * clamp_t);");
-            fragBuilder->codeAppendf("half4 colorTemp = clamp(oneMinus2t, 0.0, 1.0) * %s[0];",
+            fragBuilder->codeAppendf("float oneMinus2t = 1.0 - (2.0 * clamp_t);");
+            fragBuilder->codeAppendf("float4 colorTemp = clamp(oneMinus2t, 0.0, 1.0) * %s[0];",
                                      colors);
             fragBuilder->codeAppendf("colorTemp += (1.0 - min(abs(oneMinus2t), 1.0)) * %s[1];",
                                      colors);
@@ -1666,10 +1668,10 @@
 
     const char* fsyuni = uniformHandler->getUniformCStr(fFSYUni);
 
-    fragBuilder->codeAppendf("half2 coord = half2(%s, %s);", gradientTValue, fsyuni);
+    fragBuilder->codeAppendf("float2 coord = float2(%s, %s);", gradientTValue, fsyuni);
     fragBuilder->codeAppendf("%s = ", outputColor);
     fragBuilder->appendTextureLookupAndModulate(inputColor, texSamplers[0], "coord",
-                                                kHighFloat2_GrSLType, &fColorSpaceHelper);
+                                                kVec2f_GrSLType, &fColorSpaceHelper);
     fragBuilder->codeAppend(";");
 }