cc: Return whether any layer was scrolled from InputHandlerClient::scrollBy.

webkit/compositor_bindings/web_to_ccinput_handler_adapter.cc

 // Copyright 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.
 
 #include "web_to_ccinput_handler_adapter.h"
 
 #include "third_party/WebKit/Source/Platform/chromium/public/WebInputHandlerClient.h"
 
 #define COMPILE_ASSERT_MATCHING_ENUM(webkit_name, cc_name) \
     COMPILE_ASSERT(int(WebKit::webkit_name) == int(cc::cc_name), mismatching_enums)
@@ skipping 29 matching lines @@
 
     virtual ~ClientAdapter()
     {
     }
 
     virtual ScrollStatus scrollBegin(WebPoint point, ScrollInputType type) OVERRIDE
     {
         return static_cast<WebInputHandlerClient::ScrollStatus>(m_client->scrollBegin(point, static_cast<cc::InputHandlerClient::ScrollInputType>(type)));
     }
 
-    virtual void scrollBy(WebPoint point, WebSize offset) OVERRIDE
+    virtual void scrollBy(WebPoint point, WebSize offset)
     {
-        m_client->scrollBy(point, offset);
+        scrollByIfPossible(point, offset);
+    }
+
+    virtual bool scrollByIfPossible(WebPoint point, WebSize offset)
+    {
+      return m_client->scrollBy(point, offset);
     }
 
     virtual void scrollEnd() OVERRIDE
     {
         m_client->scrollEnd();
     }
 
     virtual void pinchGestureBegin() OVERRIDE
     {
         m_client->pinchGestureBegin();
@@ skipping 36 matching lines @@
     m_handler->bindToClient(m_clientAdapter.get());
 }
 
 void WebToCCInputHandlerAdapter::animate(base::TimeTicks time)
 {
     double monotonicTimeSeconds = (time - base::TimeTicks()).InSecondsF();
     m_handler->animate(monotonicTimeSeconds);
 }
 
 }  // namespace WebKit