Fix PrepareTextureCopyOutputResult to avoid ScopedCallbackRunner.

content/browser/compositor/surface_utils.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/compositor/surface_utils.h"
 
-#include "base/callback_helpers.h"
 #include "base/memory/ref_counted.h"
 #include "build/build_config.h"
 #include "cc/output/copy_output_result.h"
 #include "cc/resources/single_release_callback.h"
 #include "cc/surfaces/surface_id_allocator.h"
 #include "components/display_compositor/gl_helper.h"
 #include "skia/ext/image_operations.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkColorFilter.h"
 #include "third_party/skia/include/core/SkPaint.h"
@@ skipping 41 matching lines @@
     const gfx::Size& dst_size_in_pixel,
     const SkColorType color_type,
     const content::ReadbackRequestCallback& callback,
     std::unique_ptr<cc::CopyOutputResult> result) {
 #if defined(OS_ANDROID) && !defined(USE_AURA)
   // TODO(wjmaclean): See if there's an equivalent pathway for Android and
   // implement it here.
   callback.Run(SkBitmap(), content::READBACK_FAILED);
 #else
   DCHECK(result->HasTexture());
-  base::ScopedClosureRunner scoped_callback_runner(
-      base::Bind(callback, SkBitmap(), content::READBACK_FAILED));
 
   // TODO(siva.gunturi): We should be able to validate the format here using
   // GLHelper::IsReadbackConfigSupported before we processs the result.
   // See crbug.com/415682 and crbug.com/415131.
   std::unique_ptr<SkBitmap> bitmap(new SkBitmap);
   if (!bitmap->tryAllocPixels(SkImageInfo::Make(
           dst_size_in_pixel.width(), dst_size_in_pixel.height(), color_type,
           kOpaque_SkAlphaType))) {
-    scoped_callback_runner.Reset(base::Bind(

[danakj, 2016/06/24 23:57:27]

Wait this actually want to call two callbacks, with FAILED and
ALLOCATION_FAILURE?

I suspect you can instead make Reset not call the old callback, and then make
operator= do likewise. WDYT?

[Sergey Ulanov, 2016/06/27 19:41:04]

Are you saying that the old behavior is correct? That would be strange if that
|callback| was supposed to be called twice. Single operation fails once, it
cannot fail multiple times   
Also renamed Reset(closure) -> ReplaceClosure(closure) and Reset() -> RunNow().

-        callback, SkBitmap(), content::READBACK_BITMAP_ALLOCATION_FAILURE));
+    callback.Run(SkBitmap(), content::READBACK_BITMAP_ALLOCATION_FAILURE);
     return;
   }
 
   content::ImageTransportFactory* factory =
       content::ImageTransportFactory::GetInstance();
   display_compositor::GLHelper* gl_helper = factory->GetGLHelper();
-  if (!gl_helper)
+  if (!gl_helper) {
+    callback.Run(SkBitmap(), content::READBACK_FAILED);
     return;
+  }
 
   std::unique_ptr<SkAutoLockPixels> bitmap_pixels_lock(
       new SkAutoLockPixels(*bitmap));
   uint8_t* pixels = static_cast<uint8_t*>(bitmap->getPixels());
 
   cc::TextureMailbox texture_mailbox;
   std::unique_ptr<cc::SingleReleaseCallback> release_callback;
   result->TakeTexture(&texture_mailbox, &release_callback);
   DCHECK(texture_mailbox.IsTexture());
 
-  ignore_result(scoped_callback_runner.Release());
-
   gl_helper->CropScaleReadbackAndCleanMailbox(
       texture_mailbox.mailbox(), texture_mailbox.sync_token(), result->size(),
       gfx::Rect(result->size()), dst_size_in_pixel, pixels, color_type,
       base::Bind(&CopyFromCompositingSurfaceFinished, callback,
                  base::Passed(&release_callback), base::Passed(&bitmap),
                  base::Passed(&bitmap_pixels_lock)),
       display_compositor::GLHelper::SCALER_QUALITY_GOOD);
 #endif
 }
 
@@ skipping 88 matching lines @@
     return;
   }
 
   DCHECK(result->HasBitmap());
   // Software path
   PrepareBitmapCopyOutputResult(output_size_in_pixel, color_type, callback,
                                 std::move(result));
 }
 
 }  // namespace content