Make SkGrPixelRef responsible for owning GrSurface's texture rather than RT.

src/gpu/SkGrPixelRef.cpp

 
 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 
@@ skipping 88 matching lines @@
     SkImageInfo info = SkImageInfo::Make(desc.fWidth, desc.fHeight, dstCT, kPremul_SkAlphaType);
     SkGrPixelRef* pixelRef = SkNEW_ARGS(SkGrPixelRef, (info, dst));
     SkSafeUnref(dst);
     return pixelRef;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 SkGrPixelRef::SkGrPixelRef(const SkImageInfo& info, GrSurface* surface,
                            bool transferCacheLock) : INHERITED(info) {
-    // TODO: figure out if this is responsible for Chrome canvas errors
-#if 0
-    // The GrTexture has a ref to the GrRenderTarget but not vice versa.
-    // If the GrTexture exists take a ref to that (rather than the render
-    // target)
-    fSurface = surface->asTexture();
-#else
-    fSurface = NULL;
-#endif
+    // For surfaces that are both textures and render targets, the texture owns the
+    // render target but not vice versa. So we ref the texture to keep both alive for
+    // the lifetime of this pixel ref.
+    fSurface = SkSafeRef(surface->asTexture());
     if (NULL == fSurface) {
-        fSurface = surface;
+        fSurface = SkSafeRef(surface);
     }
     fUnlock = transferCacheLock;
-    SkSafeRef(surface);
 
     if (fSurface) {
         SkASSERT(info.fWidth <= fSurface->width());
         SkASSERT(info.fHeight <= fSurface->height());
     }
 }
 
 SkGrPixelRef::~SkGrPixelRef() {
     if (fUnlock) {
         GrContext* context = fSurface->getContext();
@@ skipping 46 matching lines @@
     if (!dst->allocPixels(SkImageInfo::MakeN32Premul(width, height))) {
         SkDebugf("SkGrPixelRef::onReadPixels failed to alloc bitmap for result!\n");
         return false;
     }
     SkAutoLockPixels al(*dst);
     void* buffer = dst->getPixels();
     return fSurface->readPixels(left, top, width, height,
                                 kSkia8888_GrPixelConfig,
                                 buffer, dst->rowBytes());
 }