Revert 168554 "Reduce compositing update in Silk's toggle_drawer..."

Revert 168554 "Reduce compositing update in Silk's toggle_drawer..."

This CL broke win builds:
http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Win%20Builder%20%28dbg%29/builds/47919


> Reduce compositing update in Silk's toggle_drawer by 20%
> 
> This reduces the amount of time spent in compositing update for Silk's
> toggle_drawer test case by 20%. Previously, we would update the geometry for
> every composited layer mapping during every compositing update, regardless of
> whether any of the inputs to updateGraphicsLayerGeometry had changed. This CL
> introduces dirty bits on CompositedLayerMapping to track which RenderLayers
> underwent a change that could have resulted in changes during
> updateGraphicsLayerGeometry.
> 
> This CL takes a basic approach, which is sufficient for toggle_drawer.
> Specifically, if a RenderLayer changes style, we mark its
> CompositedLayerMapping (and any ancestors and decendants) as needing a geometry
> update. If we go through layout or scroll, we trigger a forced update, which
> updates the geometry of all graphics layers.
> 
> Over time, we can improve this system to track dirtiness during layout. We
> might also be able to avoid marking every ancestor dirty if we removed the
> downward tree walks during updateGraphicsLayerGeometry. Instead, we could
> compute the descendant-dependant information in an earlier phase and detect
> whether it changed directly.
> 
> R=esprehn@chromium.org, ojan@chromium.org
> 
> Review URL: https://codereview.chromium.org/183763016

TBR=abarth@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=168556

[haraken, 2014-03-06 02:48:16]

Committed patchset #1 manually as r168556.