Defer starting of animations until after compositing update

Source/core/rendering/RenderLayerCompositor.cpp

 /*
  * Copyright (C) 2009, 2010 Apple Inc. All rights reserved.
  *
  * 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
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 383 matching lines @@
     // FIXME: We should carefully clean up the awkward early-exit semantics, balancing
     // between skipping unnecessary compositing updates and not incorrectly skipping
     // necessary updates.
 
     // Avoid updating the layers with old values. Compositing layers will be updated after the layout is finished.
     // FIXME: Can we assert that we never return here?
     if (m_renderView->needsLayout())
         return;
 
     lifecycle().advanceTo(DocumentLifecycle::InCompositingUpdate);
-    DocumentLifecycle::Scope lifecycleScope(lifecycle(), DocumentLifecycle::CompositingClean);
 
+    updateCompositingLayersInternal();
+
+    lifecycle().advanceTo(DocumentLifecycle::CompositingClean);
+
+    DocumentAnimations::startPendingAnimations(m_renderView->document());
+    DocumentAnimations::dispatchAnimationEventsAsync(m_renderView->document());

[esprehn, 2014/02/24 23:14:35]

You should ASSERT() at the end that the lifecycle() is still at
CompositingClean, DocumentAnimations in here shouldn't be allowed to make the
state move backwards.

[dstockwell, 2014/02/25 00:52:03]

Done.

+}
+
+void RenderLayerCompositor::updateCompositingLayersInternal()
+{
     if (isMainFrame() && m_renderView->frameView())
         finishCompositingUpdateForFrameTree(&m_renderView->frameView()->frame());
 
     if (m_forceCompositingMode && !m_compositing)
         enableCompositingMode(true);
 
     if (!m_needsToRecomputeCompositingRequirements && !m_compositing)
         return;
 
     TemporaryChange<bool> postLayoutChange(m_inPostLayoutUpdate, true);
@@ skipping 2331 matching lines @@
     } else if (graphicsLayer == m_scrollLayer.get()) {
         name = "Frame Scrolling Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore