cc: Move worker threads to content.

ui/compositor/compositor.h

Index: ui/compositor/compositor.h
diff --git a/ui/compositor/compositor.h b/ui/compositor/compositor.h
index 3a3e4cc829b1d675a2d3d64a7a139c69d94842a1..8f5e10e60884f442778ef010b373c02eaa323f78 100644
--- a/ui/compositor/compositor.h
+++ b/ui/compositor/compositor.h
@@ -28,6 +28,7 @@
 namespace base {
 class MessageLoopProxy;
 class RunLoop;
+class SimpleThread;
 }
 
 namespace cc {
@@ -38,6 +39,7 @@ class LayerTreeHost;
 class RendererSettings;
 class SharedBitmapManager;
 class SurfaceIdAllocator;
+class TaskGraphRunner;
 }
 
 namespace gfx {
@@ -316,6 +318,8 @@ class COMPOSITOR_EXPORT Compositor
   scoped_refptr<cc::Layer> root_web_layer_;
   scoped_ptr<cc::LayerTreeHost> host_;
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+  scoped_ptr<cc::TaskGraphRunner> task_graph_runner_;
+  scoped_ptr<base::SimpleThread> raster_thread_;
 
   // The manager of vsync parameters for this compositor.
   scoped_refptr<CompositorVSyncManager> vsync_manager_;