Merge 276305 "cc: Don't cleanup the pending twin's low res tiling."

Merge 276305 "cc: Don't cleanup the pending twin's low res tiling."

> cc: Don't cleanup the pending twin's low res tiling.
> 
> After drawing, we cull unused tilings on the active tree. If we cull
> the tiling which is the low res tiling on the pending tree, and then
> later do a pinch such that the active tree wants a tiling of that scale
> again, it would create the tiling which is already on the pending tree
> and cause a bad state.
> 
> Adds a unit test that was hitting the CHECK() in PictureLayerImpl when
> it changed the scale of the active layer to 1.f to match the pending
> layer after drawing. Now it verifies that the active layer keeps the
> pending low res tiling.
> 
> R=enne
> BUG=358350
> 
> Review URL: https://codereview.chromium.org/323193002

TBR=danakj@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=276695

[danakj, 2014-06-12 16:05:21]

Committed patchset #1 manually as r276695 (tree was closed).