[spv2] Account for flipped writing modes in paint offset

[spv2] Account for flipped writing modes in paint offset

Flipped writing modes cause an object's offset to be flipped relative
to its parent. This patch switches from using locationOffset to
topLeftLocation which includes writing mode handling. This matches
similar logic in PaintLayer::updateLayerPosition. A comment has been
added about removing unnecessary craws back up the tree for calculating
containing blocks.

With this patch, all fast/block/positioning tests pass, modulo our lack
of multicolumn fragment painting.

BUG=614257
Committed: https://crrev.com/112a79c17f09f9f1aeb2a38fc9672ff3985c7ba8
Cr-Commit-Position: refs/heads/master@{#398110}

[pdr., 2016-06-03 02:04:48]

The CQ bit was checked by pdr@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-06-03 02:05:48]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2031873005/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2031873005/1

[pdr., 2016-06-03 02:05:52]

pdr@chromium.org changed reviewers:
+ trchen@chromium.org

[commit-bot: I haz the power, 2016-06-03 04:27:47]

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

[commit-bot: I haz the power, 2016-06-03 04:27:48]

Dry run: Try jobs failed on following builders:
  linux_chromium_rel_ng on tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[pdr., 2016-06-03 04:46:25]

The CQ bit was checked by pdr@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-06-03 04:46:55]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2031873005/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2031873005/20001

[commit-bot: I haz the power, 2016-06-03 09:40:13]

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

[commit-bot: I haz the power, 2016-06-03 09:40:13]

Dry run: This issue passed the CQ dry run.

[pdr., 2016-06-06 17:42:06]

On 2016/06/03 at 09:40:13, commit-bot wrote:
> Dry run: This issue passed the CQ dry run.

Ping

[trchen, 2016-06-06 18:04:50]

lgtm. Though actually I don't have the expertise in writing modes (and many who
have it left.). I felt we should start a study group with xianzhu to figure it
out.

[pdr., 2016-06-06 18:10:11]

pdr@chromium.org changed reviewers:
+ wangxianzhu@chromium.org

[pdr., 2016-06-06 18:11:34]

+reviewer WangXianzhu, are you familiar enough with the paint properties trees
to review this? If there is anything confusing, please ask instead of spending
hours reading code.

[pdr., 2016-06-06 18:15:06]

On 2016/06/06 at 18:11:34, pdr. wrote:
> +reviewer WangXianzhu, are you familiar enough with the paint properties trees
to review this? If there is anything confusing, please ask instead of spending
hours reading code.

Just FYI: This situation is special-cased in paint invalidation because
PaintInvalidationState::supportsCachedOffsets returns false for
isFlippedBlocksWritingMode.

[Xianzhu, 2016-06-06 18:18:35]

lgtm

[pdr., 2016-06-06 18:18:49]

The CQ bit was checked by pdr@chromium.org

[commit-bot: I haz the power, 2016-06-06 18:19:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2031873005/20001

[commit-bot: I haz the power, 2016-06-06 20:18:31]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-06-06 20:19:52]

Description was changed from

==========
[spv2] Account for flipped writing modes in paint offset

Flipped writing modes cause an object's offset to be flipped relative
to its parent. This patch switches from using locationOffset to
topLeftLocation which includes writing mode handling. This matches
similar logic in PaintLayer::updateLayerPosition. A comment has been
added about removing unnecessary craws back up the tree for calculating
containing blocks.

With this patch, all fast/block/positioning tests pass, modulo our lack
of multicolumn fragment painting.

BUG=614257
==========

to

==========
[spv2] Account for flipped writing modes in paint offset

Flipped writing modes cause an object's offset to be flipped relative
to its parent. This patch switches from using locationOffset to
topLeftLocation which includes writing mode handling. This matches
similar logic in PaintLayer::updateLayerPosition. A comment has been
added about removing unnecessary craws back up the tree for calculating
containing blocks.

With this patch, all fast/block/positioning tests pass, modulo our lack
of multicolumn fragment painting.

BUG=614257

Committed: https://crrev.com/112a79c17f09f9f1aeb2a38fc9672ff3985c7ba8
Cr-Commit-Position: refs/heads/master@{#398110}
==========

[commit-bot: I haz the power, 2016-06-06 20:19:53]

Patchset 2 (id:??) landed as
https://crrev.com/112a79c17f09f9f1aeb2a38fc9672ff3985c7ba8
Cr-Commit-Position: refs/heads/master@{#398110}