Fix the animation performance issue

Fix the animation performance issue

[Title] Fix the animation performance issue
[Issue#] N/A
[Problem] Slider Puzzle: Performance is poor, app is keep stucking on any random steps even sometimes unable to start.
[Cause] Regression(http://slp-info.sec.samsung.net/gerrit/#/c/225669/)
[Solution] This issue can be resolved by r150015, but cherry-picking is hard because the current our
           local branch is different from webkit-org and there is a regression on the EFL.
           So we applied part of r150015(http://trac.webkit.org/changeset/150015)
           (refer to:https://bugs.webkit.org/show_bug.cgi?id=112345)

Conflicts:
	Source/WebKit2/WebProcess/WebPage/LayerTreeCoordinator/LayerTreeCoordinator.cpp
	Source/WebKit2/WebProcess/WebPage/LayerTreeCoordinator/LayerTreeCoordinator.h

Change-Id: Ieface03402b46e28c23ccf5dc2af0830ace8465e