All together now

ash/display/display_controller.h

Index: ash/display/display_controller.h
diff --git a/ash/display/display_controller.h b/ash/display/display_controller.h
index 97620fc93b03c08f78d5a0e815560b3db3195971..422e36f083b033196676bd770573ca95b3d56e0b 100644
--- a/ash/display/display_controller.h
+++ b/ash/display/display_controller.h
@@ -18,6 +18,7 @@
 #include "base/observer_list.h"
 #include "base/time/time.h"
 #include "ui/aura/root_window_observer.h"
+#include "ui/compositor/compositor_retriever_delegate.h"
 #include "ui/gfx/display_observer.h"
 #include "ui/gfx/point.h"
 
@@ -49,7 +50,8 @@ class RootWindowController;
 // display, keeping them in sync with display configuration changes.
 class ASH_EXPORT DisplayController : public gfx::DisplayObserver,
                                      public aura::RootWindowObserver,
-                                     public internal::DisplayManager::Delegate {
+                                     public internal::DisplayManager::Delegate,
+                                     public ui::CompositorRetrieverDelegate {
  public:
   class ASH_EXPORT Observer {
    public:
@@ -169,6 +171,10 @@ class ASH_EXPORT DisplayController : public gfx::DisplayObserver,
   virtual void PreDisplayConfigurationChange() OVERRIDE;
   virtual void PostDisplayConfigurationChange() OVERRIDE;
 
+  // ui::CompositorRetrieverDelegate overrides:
+  virtual ui::Compositor* GetCompositorForDisplay(
+      const gfx::Display& display) OVERRIDE;
+
  private:
   FRIEND_TEST_ALL_PREFIXES(DisplayControllerTest, BoundsUpdated);
   FRIEND_TEST_ALL_PREFIXES(DisplayControllerTest, SecondaryDisplayLayout);