Fix restrictions on squashing with incompatible scroll.

Fix restrictions on squashing with incompatible scroll.

The previous logic could fail in some cases when the heuristic specified for the identity of the layer to squash
into did not match exactly the choice used later in assignLayersToBackings. The new code is a bit cleaner also.

BUG=261605
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=169571

[jbroman, 2014-03-15 05:29:23]

noticed a typo while passing through

https://codereview.chromium.org/195893026/diff/1/Source/core/rendering/compos...
File Source/core/rendering/compositing/RenderLayerCompositor.cpp (right):

https://codereview.chromium.org/195893026/diff/1/Source/core/rendering/compos...
Source/core/rendering/compositing/RenderLayerCompositor.cpp:733:
ASSERT(squashignState.hasMostRecentMapping);
drive-by: squashingState not squashignState

[chrishtr, 2014-03-17 16:58:51]

https://codereview.chromium.org/195893026/diff/1/Source/core/rendering/compos...
File Source/core/rendering/compositing/RenderLayerCompositor.cpp (right):

https://codereview.chromium.org/195893026/diff/1/Source/core/rendering/compos...
Source/core/rendering/compositing/RenderLayerCompositor.cpp:733:
ASSERT(squashignState.hasMostRecentMapping);
On 2014/03/15 05:29:24, jbroman wrote:
> drive-by: squashingState not squashignState

Done.

[Ian Vollick, 2014-03-17 17:19:28]

On 2014/03/17 16:58:51, chrishtr wrote:
>
https://codereview.chromium.org/195893026/diff/1/Source/core/rendering/compos...
> File Source/core/rendering/compositing/RenderLayerCompositor.cpp (right):
> 
>
https://codereview.chromium.org/195893026/diff/1/Source/core/rendering/compos...
> Source/core/rendering/compositing/RenderLayerCompositor.cpp:733:
> ASSERT(squashignState.hasMostRecentMapping);
> On 2014/03/15 05:29:24, jbroman wrote:
> > drive-by: squashingState not squashignState
> 
> Done.

lgtm. You'll need to add an OWNER for platform/graphics.

[chrishtr, 2014-03-19 17:20:35]

Adam, ping on review.

[abarth-chromium, 2014-03-19 17:29:26]

platform/graphics LGTM

Maybe we should add @vollick as an owner for platform/graphics?

[abarth-chromium, 2014-03-19 17:29:33]

The CQ bit was checked by abarth@chromium.org

[commit-bot: I haz the power, 2014-03-19 17:29:43]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/chrishtr@chromium.org/195893026/10001

[commit-bot: I haz the power, 2014-03-19 18:47:30]

Change committed as 169571