Adding monotonic only API to Blink's animation delegate interface

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 501b806c1bfeaf9747b213368ebefba45792bea5..d628a69613c9dd3898566e3493b9bfd3974ebcb6 100644
--- a/Source/platform/graphics/GraphicsLayer.cpp
+++ b/Source/platform/graphics/GraphicsLayer.cpp
@@ -1202,13 +1202,13 @@ void GraphicsLayer::paint(GraphicsContext& context, const IntRect& clip)
 }
 
 
-void GraphicsLayer::notifyAnimationStarted(double wallClockTime, double monotonicTime, WebAnimation::TargetProperty)
+void GraphicsLayer::notifyAnimationStarted(double monotonicTime, WebAnimation::TargetProperty)
 {
     if (m_client)
-        m_client->notifyAnimationStarted(this, wallClockTime, monotonicTime);
+        m_client->notifyAnimationStarted(this, monotonicTime);
 }
 
-void GraphicsLayer::notifyAnimationFinished(double, double, WebAnimation::TargetProperty)
+void GraphicsLayer::notifyAnimationFinished(double, WebAnimation::TargetProperty)
 {
     // Do nothing.
 }