cc: Parameterize the main thread task runner

cc/test/fake_impl_proxy.h

 // Copyright 2012 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.
 
 #ifndef CC_TEST_FAKE_IMPL_PROXY_H_
 #define CC_TEST_FAKE_IMPL_PROXY_H_
 
 #include "cc/test/fake_proxy.h"
 #include "cc/trees/single_thread_proxy.h"
 
 namespace cc {
 
 class FakeImplProxy : public FakeProxy {
  public:
   FakeImplProxy() : set_impl_thread_(this) {}
 
   explicit FakeImplProxy(
       scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner)
-      : FakeProxy(impl_task_runner), set_impl_thread_(this) {}
+      : FakeProxy(base::MessageLoopProxy::current(), impl_task_runner),
+        set_impl_thread_(this) {}
 
  private:
   DebugScopedSetImplThread set_impl_thread_;
 };
 
 }  // namespace cc
 
 #endif  // CC_TEST_FAKE_IMPL_PROXY_H_