Update Context Client Visibility to use Scoped Pattern

cc/trees/layer_tree_host_impl.h

 // Copyright 2011 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_TREES_LAYER_TREE_HOST_IMPL_H_
 #define CC_TREES_LAYER_TREE_HOST_IMPL_H_
 
 #include <stddef.h>
 
 #include <bitset>
@@ skipping 24 matching lines @@
 #include "cc/resources/ui_resource_client.h"
 #include "cc/scheduler/begin_frame_tracker.h"
 #include "cc/scheduler/commit_earlyout_reason.h"
 #include "cc/scheduler/draw_result.h"
 #include "cc/scheduler/video_frame_controller.h"
 #include "cc/tiles/image_decode_controller.h"
 #include "cc/tiles/tile_manager.h"
 #include "cc/trees/layer_tree_settings.h"
 #include "cc/trees/mutator_host_client.h"
 #include "cc/trees/task_runner_provider.h"
+#include "gpu/command_buffer/client/context_support.h"
 #include "ui/gfx/geometry/rect.h"
 
 namespace gfx {
 class ScrollOffset;
 }
 
 namespace cc {
 
 class AnimationEvents;
 class AnimationHost;
@@ skipping 659 matching lines @@
   using UIResourceMap = std::unordered_map<UIResourceId, UIResourceData>;
   UIResourceMap ui_resource_map_;
 
   // Resources that were evicted by EvictAllUIResources. Resources are removed
   // from this when they are touched by a create or destroy from the UI resource
   // request queue.
   std::set<UIResourceId> evicted_ui_resources_;
 
   OutputSurface* output_surface_;
 
+  std::unique_ptr<gpu::ContextSupport::ScopedVisibility>
+      main_context_client_visibility_;
+  std::unique_ptr<gpu::ContextSupport::ScopedVisibility>
+      worker_context_client_visibility_;
+
   std::unique_ptr<ResourceProvider> resource_provider_;
   bool need_update_gpu_rasterization_status_;
   bool content_is_suitable_for_gpu_rasterization_;
   bool has_gpu_rasterization_trigger_;
   bool use_gpu_rasterization_;
   bool use_msaa_;
   GpuRasterizationStatus gpu_rasterization_status_;
   std::unique_ptr<RasterBufferProvider> raster_buffer_provider_;
   std::unique_ptr<TileTaskManager> tile_task_manager_;
   std::unique_ptr<ResourcePool> resource_pool_;
@@ skipping 105 matching lines @@
 
   std::unique_ptr<PendingTreeDurationHistogramTimer>
       pending_tree_duration_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_IMPL_H_