Remove unnecessary gl_FragCoord workaround

Bug: skia:
Change-Id: I04b6cbfe083c32a25205e04a4b15672d4b678a9c
Reviewed-on: https://skia-review.googlesource.com/c/174063
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
diff --git a/src/sksl/SkSLGLSLCodeGenerator.cpp b/src/sksl/SkSLGLSLCodeGenerator.cpp
index 26bda18..c231626 100644
--- a/src/sksl/SkSLGLSLCodeGenerator.cpp
+++ b/src/sksl/SkSLGLSLCodeGenerator.cpp
@@ -756,17 +756,9 @@
         this->write("gl_FragCoord");
     } else {
         if (!fSetupFragPositionLocal) {
-            // The Adreno compiler seems to be very touchy about access to "gl_FragCoord".
-            // Accessing glFragCoord.zw can cause a program to fail to link. Additionally,
-            // depending on the surrounding code, accessing .xy with a uniform involved can
-            // do the same thing. Copying gl_FragCoord.xy into a temp float2 beforehand
-            // (and only accessing .xy) seems to "fix" things.
-            const char* precision = usesPrecisionModifiers() ? "highp " : "";
-            fFunctionHeader += precision;
-            fFunctionHeader += "    vec2 _sktmpCoord = gl_FragCoord.xy;\n";
-            fFunctionHeader += precision;
-            fFunctionHeader += "    vec4 sk_FragCoord = vec4(_sktmpCoord.x, " SKSL_RTHEIGHT_NAME
-                               " - _sktmpCoord.y, 1.0, 1.0);\n";
+            fFunctionHeader += usesPrecisionModifiers() ? "highp " : "";
+            fFunctionHeader += "    vec4 sk_FragCoord = vec4(gl_FragCoord.x, " SKSL_RTHEIGHT_NAME
+                               " - gl_FragCoord.y, gl_FragCoord.z, gl_FragCoord.w);\n";
             fSetupFragPositionLocal = true;
         }
         this->write("sk_FragCoord");