cc: Use correct message loop proxy in BlockingTaskRunner

cc/trees/blocking_task_runner.cc

 // Copyright 2013 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 "cc/trees/blocking_task_runner.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "base/memory/singleton.h"
@@ skipping 56 matching lines @@
 bool BlockingTaskRunner::PostTask(const tracked_objects::Location& from_here,
                                   const base::Closure& task) {
   base::AutoLock lock(lock_);
   DCHECK(task_runner_.get() || capture_);
   if (!capture_)
     return task_runner_->PostTask(from_here, task);
   captured_tasks_.push_back(task);
   return true;
 }
 
+void BlockingTaskRunner::SetTaskRunner(
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner) {
+  base::AutoLock lock(lock_);
+  DCHECK(!capture_);
+  task_runner_ = task_runner;
+}
+
 void BlockingTaskRunner::SetCapture(bool capture) {
   DCHECK(BelongsToCurrentThread());
 
   std::vector<base::Closure> tasks;
 
   {
     base::AutoLock lock(lock_);
     capture_ += capture ? 1 : -1;
     DCHECK_GE(capture_, 0);
 
@@ skipping 10 matching lines @@
 BlockingTaskRunner::CapturePostTasks::CapturePostTasks()
     : blocking_runner_(BlockingTaskRunner::current()) {
   blocking_runner_->SetCapture(true);
 }
 
 BlockingTaskRunner::CapturePostTasks::~CapturePostTasks() {
   blocking_runner_->SetCapture(false);
 }
 
 }  // namespace cc