[TexMap] Flickering after transitions on Apple HTML5 demo
https://bugs.webkit.org/show_bug.cgi?id=102501

Reviewed by Noam Rosenthal.

Notify about animation start after the new animation is actually commited.

* platform/graphics/texmap/GraphicsLayerTextureMapper.cpp:
(WebCore::GraphicsLayerTextureMapper::GraphicsLayerTextureMapper):
(WebCore::GraphicsLayerTextureMapper::commitLayerChanges):
(WebCore::GraphicsLayerTextureMapper::addAnimation):
* platform/graphics/texmap/GraphicsLayerTextureMapper.h:
(GraphicsLayerTextureMapper):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@144183 268f45cc-cd09-0410-ab3c-d52691b4dbfc