cc: Get rid of LayerTreeHost::output_surface_lost_ state.

ui/views/mus/surface_context_factory.cc

 // Copyright 2015 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 "ui/views/mus/surface_context_factory.h"
 
 #include "base/memory/ptr_util.h"
 #include "cc/output/output_surface.h"
 #include "cc/resources/shared_bitmap_manager.h"
 #include "cc/surfaces/surface_id_allocator.h"
@@ skipping 77 matching lines @@
 
 cc::TaskGraphRunner* SurfaceContextFactory::GetTaskGraphRunner() {
   return raster_thread_helper_.task_graph_runner();
 }
 
 uint32_t SurfaceContextFactory::AllocateSurfaceClientId() {
   return next_surface_id_namespace_++;
 }
 
 cc::SurfaceManager* SurfaceContextFactory::GetSurfaceManager() {
-  // NOTIMPLEMENTED();
-  return nullptr;
+  return &surface_manager_;
 }
 
 void SurfaceContextFactory::SetDisplayVisible(ui::Compositor* compositor,
                                               bool visible) {
   // TODO(fsamuel): display[compositor]->SetVisible(visible);
 }
 
 void SurfaceContextFactory::ResizeDisplay(ui::Compositor* compositor,
                                           const gfx::Size& size) {
   // TODO(fsamuel): display[compositor]->Resize(size);
 }
 
 }  // namespace views