Add ScrollDirectionPhysical enum in Scroll types.

Source/core/frame/RootFrameViewport.cpp

Index: Source/core/frame/RootFrameViewport.cpp
diff --git a/Source/core/frame/RootFrameViewport.cpp b/Source/core/frame/RootFrameViewport.cpp
index e4bb2ae60eb5777fe8a20f3f53ea339fb35d7cd0..4d9db6c637bbb0b968f78cd36b83047d2a50924f 100644
--- a/Source/core/frame/RootFrameViewport.cpp
+++ b/Source/core/frame/RootFrameViewport.cpp
@@ -276,15 +276,13 @@ GraphicsLayer* RootFrameViewport::layerForVerticalScrollbar() const
     return layoutViewport().layerForVerticalScrollbar();
 }
 
-bool RootFrameViewport::scroll(ScrollDirection direction, ScrollGranularity granularity, float delta)
+bool RootFrameViewport::scroll(ScrollDirectionPhysical direction, ScrollGranularity granularity, float delta)
 {
-    ASSERT(!isLogical(direction));
-
     updateScrollAnimator();
 
     ScrollbarOrientation orientation;
 
-    if (direction == ScrollUp || direction == ScrollDown)
+    if (direction == ScrollPhysicalUp || direction == ScrollPhysicalDown)
         orientation = VerticalScrollbar;
     else
         orientation = HorizontalScrollbar;