Make WebTaskRunner ThreadSafeRefCounted

third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp

 // Copyright 2016 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 "platform/graphics/OffscreenCanvasFrameDispatcherImpl.h"
 
 #include "cc/output/compositor_frame.h"
 #include "cc/quads/texture_draw_quad.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "platform/CrossThreadFunctional.h"
@@ skipping 151 matching lines @@
   resource.is_software = false;
 
   // Hold ref to |image|, to keep it alive until the browser ReclaimResources.
   // It guarantees that the resource is not re-used or deleted.
   m_cachedImages.add(m_nextResourceId, std::move(image));
 }
 
 namespace {
 
 void updatePlaceholderImage(WeakPtr<OffscreenCanvasFrameDispatcher> dispatcher,
-                            std::unique_ptr<WebTaskRunner> taskRunner,
+                            RefPtr<WebTaskRunner> taskRunner,
                             int placeholderCanvasId,
                             RefPtr<blink::StaticBitmapImage> image,
                             unsigned resourceId) {
   DCHECK(isMainThread());
   OffscreenCanvasPlaceholder* placeholderCanvas =
       OffscreenCanvasPlaceholder::getPlaceholderById(placeholderCanvasId);
   if (placeholderCanvas) {
     placeholderCanvas->setPlaceholderFrame(std::move(image),
                                            std::move(dispatcher),
                                            std::move(taskRunner), resourceId);
@@ skipping 63 matching lines @@
     } else {
       // Case 4: both canvas and compositor are not gpu accelerated.
       commitType = CommitSoftwareCanvasSoftwareCompositing;
       setTransferableResourceToSharedBitmap(resource, image);
     }
   }
 
   // After this point, |image| can only be used on the main thread, until
   // it is returned.
   image->transfer();
-  std::unique_ptr<WebTaskRunner> dispatcherTaskRunner =
-      Platform::current()->currentThread()->getWebTaskRunner()->clone();
+  RefPtr<WebTaskRunner> dispatcherTaskRunner =
+      Platform::current()->currentThread()->getWebTaskRunner();
 
   Platform::current()->mainThread()->getWebTaskRunner()->postTask(
       BLINK_FROM_HERE,
       crossThreadBind(updatePlaceholderImage, this->createWeakPtr(),
                       WTF::passed(std::move(dispatcherTaskRunner)),
                       m_placeholderCanvasId, std::move(image), resource.id));
   m_spareResourceLocks.add(m_nextResourceId);
 
   commitTypeHistogram.count(commitType);
 
@@ skipping 183 matching lines @@
 
 void OffscreenCanvasFrameDispatcherImpl::reshape(int width, int height) {
   if (m_width != width || m_height != height) {
     m_width = width;
     m_height = height;
     m_changeSizeForNextCommit = true;
   }
 }
 
 }  // namespace blink