Null out context_factory in window_tree_host on shutdown

mojo/services/view_manager/window_tree_host_impl.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 "mojo/services/view_manager/root_node_manager.h"
 #include "mojo/services/view_manager/window_tree_host_impl.h"
 #include "mojo/public/c/gles2/gles2.h"
 #include "mojo/services/public/cpp/geometry/geometry_type_converters.h"
 #include "mojo/services/public/cpp/input_events/input_events_type_converters.h"
 #include "mojo/services/view_manager/context_factory_impl.h"
@@ skipping 71 matching lines @@
   native_viewport_.set_client(this);
   native_viewport_->Create(Rect::From(bounds));
   native_viewport_->Show();
 
   window()->SetLayoutManager(new RootLayoutManager());
 }
 
 WindowTreeHostImpl::~WindowTreeHostImpl() {
   DestroyCompositor();
   DestroyDispatcher();
+  delete context_factory_;
+  context_factory_ = NULL;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // WindowTreeHostImpl, aura::WindowTreeHost implementation:
 
 ui::EventSource* WindowTreeHostImpl::GetEventSource() {
   return this;
 }
 
 gfx::AcceleratedWidget WindowTreeHostImpl::GetAcceleratedWidget() {
@@ skipping 50 matching lines @@
 // WindowTreeHostImpl, ui::EventSource implementation:
 
 ui::EventProcessor* WindowTreeHostImpl::GetEventProcessor() {
   return dispatcher();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // WindowTreeHostImpl, NativeViewportClient implementation:
 
 void WindowTreeHostImpl::OnCreated(uint64_t native_viewport_id) {
-  LOG(ERROR) << "OnCreated " << native_viewport_id;
   CommandBufferPtr cb;
   gpu_service_->CreateOnscreenGLES2Context(
       native_viewport_id, Size::From(bounds_.size()), Get(&cb));
   widget_ = bit_cast<gfx::AcceleratedWidget>(
       static_cast<uintptr_t>(native_viewport_id));
 
   // The ContextFactory must exist before any Compositors are created.
   if (context_factory_) {
     delete context_factory_;
     context_factory_ = NULL;
@@ skipping 18 matching lines @@
 }
 
 void WindowTreeHostImpl::OnEvent(EventPtr event,
                                  const mojo::Callback<void()>& callback) {
   event_received_callback_.Run(event.Pass());
   callback.Run();
 };
 
 }  // namespace service
 }  // namespace mojo