Changing animate to beginFrame and use struct rather than naked double to allow extension.

Source/core/page/AutoscrollController.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * 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
@@ skipping 197 matching lines @@
 }
 #else
 bool AutoscrollController::panScrollInProgress() const
 {
     return false;
 }
 #endif
 
 // FIXME: This would get get better animation fidelity if it used the monotonicFrameBeginTime instead
 // of WTF::currentTime().
-void AutoscrollController::animate(double)
+void AutoscrollController::animate(blink::WebFrameTime frameTime)
 {
     if (!m_autoscrollRenderer) {
         stopAutoscroll();
         return;
     }
 
     EventHandler& eventHandler = m_autoscrollRenderer->frame()->eventHandler();
     switch (m_autoscrollType) {
     case AutoscrollForDragAndDrop:
-        if (WTF::currentTime() - m_dragAndDropAutoscrollStartTime > autoscrollDelay)
+        if (frameTime.frameTime() - m_dragAndDropAutoscrollStartTime > autoscrollDelay)
             m_autoscrollRenderer->autoscroll(m_dragAndDropAutoscrollReferencePosition);
         break;
     case AutoscrollForSelection:
         if (!eventHandler.mousePressed()) {
             stopAutoscroll();
             return;
         }
         eventHandler.updateSelectionForMouseDrag();
         m_autoscrollRenderer->autoscroll(eventHandler.lastKnownMousePosition());
         break;
@@ skipping 51 matching lines @@
     } else if (east)
         view->setCursor(eastPanningCursor());
     else if (west)
         view->setCursor(westPanningCursor());
     else
         view->setCursor(middlePanningCursor());
 }
 #endif
 
 } // namespace WebCore