Implement NVPR on GLES

src/gpu/gl/GrGLPathRendering.cpp

Index: src/gpu/gl/GrGLPathRendering.cpp
diff --git a/src/gpu/gl/GrGLPathRendering.cpp b/src/gpu/gl/GrGLPathRendering.cpp
index 249d98139ad65b9d888e161ba32c7f6281a52046..43ef827140963bd1e2709a9da7188d1f305289cc 100644
--- a/src/gpu/gl/GrGLPathRendering.cpp
+++ b/src/gpu/gl/GrGLPathRendering.cpp
@@ -37,7 +37,10 @@ class GrGLPathRenderingV13 : public GrGLPathRenderingV12 {
 public:
     GrGLPathRenderingV13(const GrGLInterface* glInterface)
         : GrGLPathRenderingV12(glInterface) {
-        fCaps.fragmentInputGenSupport = true;
+        // Using ProgramPathFragmentInputGen on OpenGL triggers a bug that manifests itself
+        // sometimes when running shadertext test. Valgrind catches the problem reproducibly.
+        // TODO: remove this once this is fixed in the driver.
+        fCaps.fragmentInputGenSupport = kGLES_GrGLStandard == glInterface->fStandard;
     }
 
     virtual GrGLvoid programPathFragmentInputGen(GrGLuint program, GrGLint location,