Implement CSSOM Smooth Scroll API

Source/platform/graphics/GraphicsLayer.cpp

Index: Source/platform/graphics/GraphicsLayer.cpp
diff --git a/Source/platform/graphics/GraphicsLayer.cpp b/Source/platform/graphics/GraphicsLayer.cpp
index bbaf60a139151ff3397c7544d5bf0d699e8c255c..1ae5f2a95cd570fffe847bdf643b8e8bea88eda2 100644
--- a/Source/platform/graphics/GraphicsLayer.cpp
+++ b/Source/platform/graphics/GraphicsLayer.cpp
@@ -1213,15 +1213,22 @@ void GraphicsLayer::paint(GraphicsContext& context, const IntRect& clip)
 }
 
 
-void GraphicsLayer::notifyAnimationStarted(double wallClockTime, double monotonicTime, WebAnimation::TargetProperty)
+void GraphicsLayer::notifyAnimationStarted(double wallClockTime, double monotonicTime, WebAnimation::TargetProperty targetProperty)
 {
+    if (targetProperty == WebAnimation::TargetPropertyScrollOffset) {
+        if (m_scrollableArea)
+            m_scrollableArea->notifyAnimationStarted(monotonicTime);
+        return;
+    }
+
     if (m_client)
         m_client->notifyAnimationStarted(this, wallClockTime, monotonicTime);
 }
 
-void GraphicsLayer::notifyAnimationFinished(double, double, WebAnimation::TargetProperty)
+void GraphicsLayer::notifyAnimationFinished(double wallClockTime, double monotonicTime, WebAnimation::TargetProperty targetProperty)
 {
-    // Do nothing.
+    if (targetProperty == WebAnimation::TargetPropertyScrollOffset && m_scrollableArea)
+        m_scrollableArea->notifyAnimationStarted(monotonicTime);

[Ian Vollick, 2014/02/06 16:02:31]

Hmm. This is confusing at a glance. Could you add a comment explaining why you
notifyAnimationStarted from notifyAnimationFinished? Was this supposed to be
notifyAnimationFinished?

 }
 
 void GraphicsLayer::didScroll()