Make GPU coord transforms automatic

src/effects/gradients/SkLinearGradient.cpp

Index: src/effects/gradients/SkLinearGradient.cpp
diff --git a/src/effects/gradients/SkLinearGradient.cpp b/src/effects/gradients/SkLinearGradient.cpp
index aa8486d3c86684aafa066bc31f2640e4e3bdb6a2..5563a03f7e1d6ad5db84024396749568d4b22b01 100644
--- a/src/effects/gradients/SkLinearGradient.cpp
+++ b/src/effects/gradients/SkLinearGradient.cpp
@@ -448,6 +448,7 @@ public:
                           EffectKey,
                           const char* outputColor,
                           const char* inputColor,
+                          const TransformedCoordsArray&,
                           const TextureSamplerArray&) SK_OVERRIDE;
 
     static EffectKey GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
@@ -522,12 +523,10 @@ void GrGLLinearGradient::emitCode(GrGLShaderBuilder* builder,
                                   EffectKey key,
                                   const char* outputColor,
                                   const char* inputColor,
+                                  const TransformedCoordsArray& coords,
                                   const TextureSamplerArray& samplers) {
     this->emitUniforms(builder, key);
-    SkString coords;
-    this->setupMatrix(builder, key, &coords);
-    SkString t;
-    t.append(coords);
+    SkString t = builder->ensureFSCoords2D(coords, 0);
     t.append(".x");
     this->emitColor(builder, t.c_str(), key, outputColor, inputColor, samplers);
 }