Plumb CompositingReason from Blink to compositor.

public/platform/WebLayer.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 11 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef WebLayer_h
 #define WebLayer_h
 
 #include "WebAnimation.h"
 #include "WebColor.h"
 #include "WebCommon.h"
+#include "WebCompositingReasons.h"
 
 // Remove after making setPositionConstraint() pure virtual.
 #include "WebLayerPositionConstraint.h"
 
 #include "WebPoint.h"
 #include "WebPrivatePtr.h"
 #include "WebRect.h"
 #include "WebString.h"
 #include "WebVector.h"
 
@@ skipping 91 matching lines @@
 
     // Apply filters to pixels that show through the background of this layer.
     // Note: These filters are only possible on layers that are drawn directly
     // to a root render surface with an opaque background. This means if an
     // ancestor of the background-filtered layer sets certain properties
     // (opacity, transforms), it may conflict and hide the background filters.
     virtual void setBackgroundFilters(const WebFilterOperations&) = 0;
 
     virtual void setDebugName(WebString) = 0;
 
+    // Provides a bitfield that describe why this composited layer was created.
+    // FIXME: non-pure until the chromium-side implements this.
+    virtual void setCompositingReasons(WebCompositingReasons) { }
+
     // An animation delegate is notified when animations are started and
     // stopped. The WebLayer does not take ownership of the delegate, and it is
     // the responsibility of the client to reset the layer's delegate before
     // deleting the delegate.
     virtual void setAnimationDelegate(WebAnimationDelegate*) = 0;
 
     // Returns false if the animation cannot be added.
     virtual bool addAnimation(WebAnimation*) = 0;
 
     // Removes all animations with the given id.
@@ skipping 62 matching lines @@
     virtual bool isOrphan() const = 0;
 
     // DEPRECATED
     virtual void setFixedToContainerLayer(bool) { }
     virtual bool fixedToContainerLayer() const { return positionConstraint().isFixedPosition; }
 };
 
 } // namespace WebKit
 
 #endif // WebLayer_h