Draw the offscreen texture to reflector's surface without extra copy

content/browser/compositor/reflector_impl.h

Index: content/browser/compositor/reflector_impl.h
diff --git a/content/browser/compositor/reflector_impl.h b/content/browser/compositor/reflector_impl.h
index 7f3b9fc4fe5ef3b63593e8dc6845f3447325114e..957dfc305fae5f638789f79c5b6dece329c4d693 100644
--- a/content/browser/compositor/reflector_impl.h
+++ b/content/browser/compositor/reflector_impl.h
@@ -5,6 +5,7 @@
 #ifndef CONTENT_BROWSER_COMPOSITOR_REFLECTOR_IMPL_H_
 #define CONTENT_BROWSER_COMPOSITOR_REFLECTOR_IMPL_H_
 
+#include "base/callback.h"
 #include "base/id_map.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
@@ -13,6 +14,7 @@
 #include "content/browser/compositor/image_transport_factory.h"
 #include "content/common/content_export.h"
 #include "gpu/command_buffer/common/mailbox_holder.h"
+#include "ui/compositor/compositor_observer.h"
 #include "ui/compositor/reflector.h"
 #include "ui/gfx/geometry/size.h"
 
@@ -34,7 +36,8 @@ class BrowserCompositorOutputSurface;
 // to the texture, then draw it onto the mirroring compositor.
 class CONTENT_EXPORT ReflectorImpl
     : public base::SupportsWeakPtr<ReflectorImpl>,
-      public ui::Reflector {
+      public ui::Reflector,
+      public ui::CompositorObserver {
  public:
   ReflectorImpl(ui::Compositor* mirrored_compositor,
                 ui::Layer* mirroring_layer);
@@ -46,11 +49,20 @@ class CONTENT_EXPORT ReflectorImpl
 
   void DetachFromOutputSurface();
 
-  // ui::Reflector implementation.
+  // ui::Reflector:
   void OnMirroringCompositorResized() override;
   void AddMirroringLayer(ui::Layer* layer) override;
   void RemoveMirroringLayer(ui::Layer* layer) override;
 
+  // ui::CompositorObserver:
+  void OnCompositingDidCommit(ui::Compositor* compositor) override {}
+  void OnCompositingStarted(ui::Compositor* compositor,
+                            base::TimeTicks start_time) override;
+  void OnCompositingEnded(ui::Compositor* compositor) override {}
+  void OnCompositingAborted(ui::Compositor* compositor) override {}
+  void OnCompositingLockStateChanged(ui::Compositor* compositor) override {}
+  void OnCompositingShuttingDown(ui::Compositor* compositor) override {}
+
   // Called in |BrowserCompositorOutputSurface::SwapBuffers| to copy
   // the full screen image to the |mailbox_| texture.
   void OnSourceSwapBuffers();
@@ -62,6 +74,10 @@ class CONTENT_EXPORT ReflectorImpl
   // Called when the source surface is bound and available.
   void OnSourceSurfaceReady(BrowserCompositorOutputSurface* surface);
 
+  // Called when the mailbox which has the source surface's texture
+  // is updated.
+  void OnSourceTextureMailboxUpdated(scoped_refptr<OwnedMailbox> mailbox);
+
  private:
   struct LayerData;
 
@@ -73,11 +89,12 @@ class CONTENT_EXPORT ReflectorImpl
 
   ui::Compositor* mirrored_compositor_;
   ScopedVector<LayerData> mirroring_layers_;
+
   scoped_refptr<OwnedMailbox> mailbox_;
-  scoped_ptr<GLHelper> mirrored_compositor_gl_helper_;
-  int mirrored_compositor_gl_helper_texture_id_;
   bool flip_texture_;
+  int composition_count_;
   BrowserCompositorOutputSurface* output_surface_;
+  base::Closure composition_started_callback_;
 };
 
 }  // namespace content