(not for commit) Simplified multi-threaded Ganesh with lock on Flush only.

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 <set>
 #include <string>
 #include <vector>
@@ skipping 11 matching lines @@
 #include "cc/input/input_handler.h"
 #include "cc/input/layer_scroll_offset_delegate.h"
 #include "cc/input/top_controls_manager_client.h"
 #include "cc/layers/layer_lists.h"
 #include "cc/layers/render_pass_sink.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/output/managed_memory_policy.h"
 #include "cc/output/output_surface_client.h"
 #include "cc/output/renderer.h"
 #include "cc/quads/render_pass.h"
+#include "cc/resources/gpu_tile_task_worker_pool.h"
 #include "cc/resources/rasterizer.h"
 #include "cc/resources/resource_provider.h"
 #include "cc/resources/tile_manager.h"
 #include "cc/scheduler/commit_earlyout_reason.h"
 #include "cc/scheduler/draw_result.h"
 #include "skia/ext/refptr.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/geometry/rect.h"
 
 namespace cc {
 
 class CompletionEvent;
 class CompositorFrameMetadata;
 class DebugRectHistory;
 class EvictionTilePriorityQueue;
 class FrameRateCounter;
 class LayerImpl;
 class LayerTreeImpl;
 class MemoryHistory;
 class PageScaleAnimation;
 class PaintTimeCounter;
 class PictureLayerImpl;
 class RasterTilePriorityQueue;
 class TileTaskWorkerPool;
+class Rasterizer;
 class RenderPassDrawQuad;
 class RenderingStatsInstrumentation;
 class ResourcePool;
 class ScrollElasticityHelper;
 class ScrollbarLayerImplBase;
 class TextureMailboxDeleter;
 class TopControlsManager;
 class UIResourceBitmap;
 class UIResourceRequest;
 struct RendererCapabilitiesImpl;
@@ skipping 663 matching lines @@
 
   bool requires_high_res_to_draw_;
   bool required_for_draw_tile_is_top_of_raster_queue_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHostImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_IMPL_H_