Get gradient information for gpu effect directly from SkGradientShader instead of calling asAGradie…

src/effects/gradients/SkGradientShader.cpp

Index: src/effects/gradients/SkGradientShader.cpp
diff --git a/src/effects/gradients/SkGradientShader.cpp b/src/effects/gradients/SkGradientShader.cpp
index 3547fbec94f4e372c5ee3dc70e7c0bd4a03effdd..58c4a511784c7a58371a04377fe528f6470430c1 100644
--- a/src/effects/gradients/SkGradientShader.cpp
+++ b/src/effects/gradients/SkGradientShader.cpp
@@ -203,6 +203,18 @@ void SkGradientShaderBase::flatten(SkWriteBuffer& buffer) const {
     buffer.writeMatrix(fPtsToUnit);
 }
 
+void SkGradientShaderBase::getGradientDescriptorGpu(DescriptorGpu* desc) const {
+    desc->fCount = fColorCount;
+    if (fColorCount <= 3) {
+        memcpy(desc->fColors, fOrigColors, fColorCount * sizeof(SkColor));
+    }
+    if (3 == fColorCount){
+        desc->fMidPos = SkFixedToScalar(fRecs[1].fPos);
+    }
+    desc->fTileMode = fTileMode;
+    desc->fFlags = fGradFlags;
+}
+
 bool SkGradientShaderBase::isOpaque() const {
     return fColorsAreOpaque;
 }
@@ -1005,31 +1017,27 @@ GrGradientEffect::GrGradientEffect(GrContext* ctx,
                                    SkShader::TileMode tileMode) {
 
     fIsOpaque = shader.isOpaque();
+    SkGradientShaderBase::DescriptorGpu gradDesc;
 
-    SkShader::GradientInfo info;
-    SkScalar pos[3] = {0};
-
-    info.fColorCount = 3;
-    info.fColors = &fColors[0];
-    info.fColorOffsets = &pos[0];
-    shader.asAGradient(&info);
+    gradDesc.fColors = &fColors[0];
+    shader.getGradientDescriptorGpu(&gradDesc);
 
     // The two and three color specializations do not currently support tiling.
     bool foundSpecialCase = false;
-    if (SkShader::kClamp_TileMode == info.fTileMode) {
-        if (2 == info.fColorCount) {
+    if (SkShader::kClamp_TileMode == gradDesc.fTileMode) {
+        if (2 == gradDesc.fCount) {
             fRow = -1; // flag for no atlas
             fColorType = kTwo_ColorType;
             foundSpecialCase = true;
-        } else if (3 == info.fColorCount &&
-                   (SkScalarAbs(pos[1] - SK_ScalarHalf) < SK_Scalar1 / 1000)) { // 3 color symmetric
+        } else if (3 == gradDesc.fCount &&
+                   (SkScalarAbs(gradDesc.fMidPos - SK_ScalarHalf) < SK_Scalar1 / 1000)) { // 3 color symmetric
             fRow = -1; // flag for no atlas
             fColorType = kThree_ColorType;
             foundSpecialCase = true;
         }
     }
     if (foundSpecialCase) {
-        if (SkGradientShader::kInterpolateColorsInPremul_Flag & info.fGradientFlags) {
+        if (SkGradientShader::kInterpolateColorsInPremul_Flag & gradDesc.fFlags) {
             fPremulType = kBeforeInterp_PremulType;
         } else {
             fPremulType = kAfterInterp_PremulType;