Don't schedule an animation during compositing dirty-bit setting unless needed.

Source/core/page/PageAnimator.h

Index: Source/core/page/PageAnimator.h
diff --git a/Source/core/page/PageAnimator.h b/Source/core/page/PageAnimator.h
index 47a4b9cbe24afecde3d8ba429bb2b85eae179f0f..5c8d9e5c240fe776b1aec25fd6f523d2b0f66920 100644
--- a/Source/core/page/PageAnimator.h
+++ b/Source/core/page/PageAnimator.h
@@ -18,11 +18,13 @@ public:
 
     void setAnimationFramePending() { m_animationFramePending = true; }
     bool isServicingAnimations() const { return m_servicingAnimations; }
+    void updateLayoutAndStyleForPainting();
 
 private:
     Page* m_page;
     bool m_animationFramePending;
     bool m_servicingAnimations;
+    bool m_updatingLayoutAndStyleForPainting;
 };
 
 }