Implement external stencil for Android WebView

cc/output/output_surface.cc

 // Copyright (c) 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/output/output_surface.h"
 
 #include <stdint.h>
 
 #include "base/bind.h"
 #include "base/location.h"
@@ skipping 173 matching lines @@
 
 OutputSurface::~OutputSurface() {
   if (client_)
     DetachFromClientInternal();
 }
 
 bool OutputSurface::HasExternalStencilTest() const {
   return external_stencil_test_enabled_;
 }
 
+void OutputSurface::ApplyExternalStencil() {}
+
 bool OutputSurface::BindToClient(OutputSurfaceClient* client) {
   DCHECK(client_thread_checker_.CalledOnValidThread());
   DCHECK(client);
   DCHECK(!client_);
   client_ = client;
   bool success = true;
 
   if (context_provider_.get()) {
     success = context_provider_->BindToCurrentThread();
     if (success) {
@@ skipping 150 matching lines @@
   if (context_provider_.get()) {
     context_provider_->SetLostContextCallback(
         ContextProvider::LostContextCallback());
   }
   context_provider_ = nullptr;
   client_ = nullptr;
   weak_ptr_factory_.InvalidateWeakPtrs();
 }
 
 }  // namespace cc