Revert of Revert ""Revert of eliminate config param -- it was always self's config (https://codereview.chromi…

src/gpu/SkGrPixelRef.cpp

Index: src/gpu/SkGrPixelRef.cpp
diff --git a/src/gpu/SkGrPixelRef.cpp b/src/gpu/SkGrPixelRef.cpp
index 85de28577961bc70d9994238391479252a669fbf..fd21f1073bf1560a34a95d8b0ac8cdecebd22d33 100644
--- a/src/gpu/SkGrPixelRef.cpp
+++ b/src/gpu/SkGrPixelRef.cpp
@@ -51,7 +51,8 @@
 
 ///////////////////////////////////////////////////////////////////////////////
 
-static SkGrPixelRef* copyToTexturePixelRef(GrTexture* texture, const SkIRect* subset) {
+static SkGrPixelRef* copyToTexturePixelRef(GrTexture* texture, SkBitmap::Config dstConfig,
+                                           const SkIRect* subset) {
     if (NULL == texture) {
         return NULL;
     }
@@ -76,7 +77,7 @@
         topLeft = NULL;
     }
     desc.fFlags = kRenderTarget_GrTextureFlagBit | kNoStencil_GrTextureFlagBit;
-    desc.fConfig = texture->config();
+    desc.fConfig = SkBitmapConfig2GrPixelConfig(dstConfig);
 
     SkImageInfo info;
     if (!GrPixelConfig2ColorType(desc.fConfig, &info.fColorType)) {
@@ -151,7 +152,7 @@
     return NULL;
 }
 
-SkPixelRef* SkGrPixelRef::deepCopy(const SkIRect* subset) {
+SkPixelRef* SkGrPixelRef::deepCopy(SkBitmap::Config dstConfig, const SkIRect* subset) {
     if (NULL == fSurface) {
         return NULL;
     }
@@ -162,7 +163,7 @@
     // a GrTexture owned elsewhere (e.g., SkGpuDevice), and cannot live
     // independently of that texture.  Texture-backed pixel refs, on the other
     // hand, own their GrTextures, and are thus self-contained.
-    return copyToTexturePixelRef(fSurface->asTexture(), subset);
+    return copyToTexturePixelRef(fSurface->asTexture(), dstConfig, subset);
 }
 
 bool SkGrPixelRef::onReadPixels(SkBitmap* dst, const SkIRect* subset) {