Add a number of tests for layer squashing

Add a number of tests for layer squashing

This CL converts a number of manual tests from crbug.com/315321 into
LayoutTests. In this CL, I've converted a number of simple cases from
comment 2 on that issue. In a future CL, I'll convert more tests.

BUG=315321
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=166865

[shawnsingh, 2014-01-27 21:35:26]

Very cool =)  Two comments:

https://codereview.chromium.org/137143009/diff/1/LayoutTests/compositing/squa...
File LayoutTests/compositing/squashing/squash-clipped-expected.txt (right):

https://codereview.chromium.org/137143009/diff/1/LayoutTests/compositing/squa...
LayoutTests/compositing/squashing/squash-clipped-expected.txt:28: (bounds 260.00
260.00)
It makes sense that these bounds are 260x260, but that means there's no
indication in the test results that it was properly clipped.  If nothing else,
maybe we make this a pixel test to capture the clipping correctness.  Or perhaps
there's a better way that I'm not aware of...

https://codereview.chromium.org/137143009/diff/1/LayoutTests/compositing/squa...
File LayoutTests/compositing/squashing/squash-onto-nephew.html (right):

https://codereview.chromium.org/137143009/diff/1/LayoutTests/compositing/squa...
LayoutTests/compositing/squashing/squash-onto-nephew.html:83: <div
class="composited box behind"></div>
Actually my manual test for this was outdated, sorry about that.  This test
existed before we force-composited the first squashable layer.  To test this
correctly with the new code, we need the first squashable RenderLayer to be a
nephew of the subsequent squashable layers.  So I think it would work perfectly
to move the class="middle" layer to live inside this class="container" element,
adjusting positions accordingly.

[abarth-chromium, 2014-01-28 22:17:38]

Done on both counts.  PTAL.

[shawnsingh, 2014-01-28 22:56:25]

LGTM with only one issue.

https://codereview.chromium.org/137143009/diff/40001/LayoutTests/compositing/...
File LayoutTests/compositing/squashing/squash-onto-nephew-expected.txt (right):

https://codereview.chromium.org/137143009/diff/40001/LayoutTests/compositing/...
LayoutTests/compositing/squashing/squash-onto-nephew-expected.txt:26: (bounds
300.00 300.00)
I tested this on canary... unfortunately squashing does not do what I expect to
be correct.  Maybe we have to remove this test from this patch and create a bug
for it.

[abarth-chromium, 2014-01-28 23:01:42]

https://codereview.chromium.org/137143009/diff/40001/LayoutTests/compositing/...
File LayoutTests/compositing/squashing/squash-onto-nephew-expected.txt (right):

https://codereview.chromium.org/137143009/diff/40001/LayoutTests/compositing/...
LayoutTests/compositing/squashing/squash-onto-nephew-expected.txt:26: (bounds
300.00 300.00)
On 2014/01/28 22:56:25, shawnsingh wrote:
> I tested this on canary... unfortunately squashing does not do what I expect
to
> be correct.  Maybe we have to remove this test from this patch and create a
bug
> for it.

What behavior do you think is correct?  We can land the test with the correct
expectation and file a bug about not matching it.

[shawnsingh, 2014-01-28 23:39:50]

On 2014/01/28 23:01:42, abarth wrote:
>
https://codereview.chromium.org/137143009/diff/40001/LayoutTests/compositing/...
> File LayoutTests/compositing/squashing/squash-onto-nephew-expected.txt
(right):
> 
>
https://codereview.chromium.org/137143009/diff/40001/LayoutTests/compositing/...
> LayoutTests/compositing/squashing/squash-onto-nephew-expected.txt:26: (bounds
> 300.00 300.00)
> On 2014/01/28 22:56:25, shawnsingh wrote:
> > I tested this on canary... unfortunately squashing does not do what I expect
> to
> > be correct.  Maybe we have to remove this test from this patch and create a
> bug
> > for it.
> 
> What behavior do you think is correct?  We can land the test with the correct
> expectation and file a bug about not matching it.

Good idea - I attached a manually created dump of the tree I would expect on the
associated bug - crbug.com/315321

Basically the structure should be like this:

Root
    - Frame
        - overflow hidden container
            - squashing no-op layer
                - m_ancestorClipLayer (300x300)
                    - the actual nephew that is force composited (100x100)
                - m_squashingLayer (180x190)


I think I got the positioning wrong on a few of the layers, though.

[abarth-chromium, 2014-02-04 20:48:33]

The CQ bit was checked by abarth@chromium.org

[commit-bot: I haz the power, 2014-02-04 20:50:45]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/abarth@chromium.org/137143009/40001

[commit-bot: I haz the power, 2014-02-04 22:43:00]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-02-04 22:43:00]

Retried try job too often on win_blink_rel for step(s) blink_heap_unittests,
blink_platform_unittests, webkit_lint, webkit_python_tests, webkit_tests,
webkit_unit_tests, wtf_unittests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_blink_...

[abarth-chromium, 2014-02-04 23:07:00]

The CQ bit was checked by abarth@chromium.org

[commit-bot: I haz the power, 2014-02-04 23:07:13]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/abarth@chromium.org/137143009/40001

[commit-bot: I haz the power, 2014-02-05 00:05:57]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-02-05 00:05:58]

Retried try job too often on win_blink_rel for step(s) blink_heap_unittests,
blink_platform_unittests, webkit_lint, webkit_python_tests, webkit_tests,
webkit_unit_tests, wtf_unittests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_blink_...

[shawnsingh, 2014-02-05 00:19:45]

On 2014/02/05 00:05:58, I haz the power (commit-bot) wrote:
> Retried try job too often on win_blink_rel for step(s) blink_heap_unittests,
> blink_platform_unittests, webkit_lint, webkit_python_tests, webkit_tests,
> webkit_unit_tests, wtf_unittests
>
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_blink_...

looks like the squash-transform.html test is triggering a known crasher bug -
https://code.google.com/p/chromium/issues/detail?id=336563

I think it would be reasonable to just remove that test for now to get the other
tests landed.

[abarth-chromium, 2014-02-10 18:42:34]

The CQ bit was checked by abarth@chromium.org

[commit-bot: I haz the power, 2014-02-10 18:42:45]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/abarth@chromium.org/137143009/220001

[abarth-chromium, 2014-02-10 20:42:47]

The CQ bit was checked by abarth@chromium.org

[commit-bot: I haz the power, 2014-02-10 20:42:58]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/abarth@chromium.org/137143009/340001

[commit-bot: I haz the power, 2014-02-10 22:01:21]

Change committed as 166865