Revert of GrContext::copyTexture->GrContext::copySurface. Add a flush writes pixel ops flag.

src/image/SkSurface_Gpu.cpp

Index: src/image/SkSurface_Gpu.cpp
diff --git a/src/image/SkSurface_Gpu.cpp b/src/image/SkSurface_Gpu.cpp
index fb087ea24bb26efe542d135a2a9e497afd74fa59..024c151cea9fb73a146f5269d96c66e300827e3c 100644
--- a/src/image/SkSurface_Gpu.cpp
+++ b/src/image/SkSurface_Gpu.cpp
@@ -89,7 +89,7 @@
             fDevice->createCompatibleDevice(fDevice->imageInfo()));
         SkAutoTUnref<SkGpuDevice> aurd(newDevice);
         if (kRetain_ContentChangeMode == mode) {
-            fDevice->context()->copySurface(newDevice->accessRenderTarget(), rt->asTexture());
+            fDevice->context()->copyTexture(rt->asTexture(), newDevice->accessRenderTarget());
         }
         SkASSERT(this->getCachedCanvas());
         SkASSERT(this->getCachedCanvas()->getDevice() == fDevice);