Get rid of HitTestChildBlockBackground walk.

Get rid of HitTestChildBlockBackground walk.

I'm not 100% what this was for, but looking at Blink,
it appears that HitTestChildBlockBackground being different
from HitTestBlockBackground had something to do with
multi-column/regions, which we don't have. I believe
this patch doesn't change any behavior.

Also added to the elementFromPoint test in order to
get more test coverage of the hitTesting code.

R=abarth@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/ed0316fc3b31da1686163f3161c063983c1ab43c

[ojan, 2015-02-14 03:25:49]

ojan@chromium.org changed reviewers:
+ abarth@chromium.org, eseidel@chromium.org, esprehn@chromium.org

[ojan, 2015-02-14 03:25:49]

https://codereview.chromium.org/924263002/diff/1/sky/engine/core/rendering/Re...
File sky/engine/core/rendering/RenderObject.cpp (left):

https://codereview.chromium.org/924263002/diff/1/sky/engine/core/rendering/Re...
sky/engine/core/rendering/RenderObject.cpp:1686: inside = nodeAtPoint(request,
result, locationInContainer, accumulatedOffset, HitTestChildBlockBackgrounds);
If the hitTest is in a child block's background it will still hit in the
HitTestBlockBackground call below.

[abarth-chromium, 2015-02-14 04:18:01]

lgtm

[ojan, 2015-02-14 05:06:05]

Committed patchset #1 (id:1) manually as
ed0316fc3b31da1686163f3161c063983c1ab43c (presubmit successful).