cc: Make OutputSurface::BindToClient pure virtual and not return bool

cc/test/fake_output_surface_client.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/test/fake_output_surface_client.h"
 
 namespace cc {
 
 void FakeOutputSurfaceClient::DidReceiveSwapBuffersAck() {
   swap_count_++;
 }
 
-void FakeOutputSurfaceClient::DidLoseOutputSurface() {
-  did_lose_output_surface_called_ = true;
-}
-
 }  // namespace cc