Draw omnibox shadow with a ninebox layer.

ui/compositor/compositor.h

 // Copyright (c) 2012 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 UI_COMPOSITOR_COMPOSITOR_H_
 #define UI_COMPOSITOR_COMPOSITOR_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 281 matching lines @@
   // The compositor must be set to invisible when taking away a widget.
   gfx::AcceleratedWidget ReleaseAcceleratedWidget();
   gfx::AcceleratedWidget widget() const;
 
 #if defined(USE_AURA)
   // Sets the window for the compositor to render into on mus+ash.
   void SetWindow(ui::Window* window);
   ui::Window* window() const;
 #endif
 
+cc::LayerTreeHost* layer_tree_host() { return host_.get(); }
+
   // Returns the vsync manager for this compositor.
   scoped_refptr<CompositorVSyncManager> vsync_manager() const;
 
   // Returns the main thread task runner this compositor uses. Users of the
   // compositor generally shouldn't use this.
   scoped_refptr<base::SingleThreadTaskRunner> task_runner() const {
     return task_runner_;
   }
 
   // Compositor does not own observers. It is the responsibility of the
@@ skipping 117 matching lines @@
   gfx::ColorSpace color_space_;
 
   base::WeakPtrFactory<Compositor> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Compositor);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_COMPOSITOR_H_