Don't flush on copyTexture, take 2

src/gpu/SkGrPixelRef.cpp

Index: src/gpu/SkGrPixelRef.cpp
diff --git a/src/gpu/SkGrPixelRef.cpp b/src/gpu/SkGrPixelRef.cpp
index 8b68448e41bf0216195d2497cfe5042ec659cccf..9f2bb452c9cfb0fec004e2cd1a7e95d45058dc9e 100644
--- a/src/gpu/SkGrPixelRef.cpp
+++ b/src/gpu/SkGrPixelRef.cpp
@@ -53,8 +53,8 @@ bool SkROLockPixelsPixelRef::onLockPixelsAreWritable() const {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-static SkGrPixelRef* copyToTexturePixelRef(GrTexture* texture, SkColorType dstCT,
-                                           const SkIRect* subset) {
+static SkGrPixelRef* copy_to_new_texture_pixelref(GrTexture* texture, SkColorType dstCT,
+                                                  const SkIRect* subset) {
     if (NULL == texture || kUnknown_SkColorType == dstCT) {
         return NULL;
     }
@@ -88,15 +88,10 @@ static SkGrPixelRef* copyToTexturePixelRef(GrTexture* texture, SkColorType dstCT
 
     context->copyTexture(texture, dst->asRenderTarget(), topLeft);
 
-    // TODO: figure out if this is responsible for Chrome canvas errors
-#if 0
-    // The render texture we have created (to perform the copy) isn't fully
-    // functional (since it doesn't have a stencil buffer). Release it here
-    // so the caller doesn't try to render to it.
-    // TODO: we can undo this release when dynamic stencil buffer attach/
-    // detach has been implemented
-    dst->releaseRenderTarget();
-#endif
+    // Blink is relying on the above copy being sent to GL immediately in the case when the source
+    // is a WebGL canvas backing store. We could have a TODO to remove this flush, but we have a
+    // larger TODO to remove SkGrPixelRef entirely.
+    context->flush();
 
     SkImageInfo info = SkImageInfo::Make(desc.fWidth, desc.fHeight, dstCT, kPremul_SkAlphaType);
     SkGrPixelRef* pixelRef = SkNEW_ARGS(SkGrPixelRef, (info, dst));