Make WebTaskRunner ThreadSafeRefCounted

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

Index: third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp b/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp
index cf252bf58aed11cf8b00cd84356980beb795dd20..7496236290c9fd01a4f90853dcada202472d78eb 100644
--- a/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp
+++ b/third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp
@@ -158,7 +158,7 @@ void OffscreenCanvasFrameDispatcherImpl::
 namespace {
 
 void updatePlaceholderImage(WeakPtr<OffscreenCanvasFrameDispatcher> dispatcher,
-                            std::unique_ptr<WebTaskRunner> taskRunner,
+                            RefPtr<WebTaskRunner> taskRunner,
                             int placeholderCanvasId,
                             RefPtr<blink::Image> image,
                             unsigned resourceId) {
@@ -243,8 +243,8 @@ void OffscreenCanvasFrameDispatcherImpl::dispatchFrame(
   // 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,