Resolve percentage in <use> against the instance's viewport element

Resolve percentage in <use> against the instance's viewport element

In LayoutSVGTransformableContainer::calculateLocalTransform, 'x' and 'y'
were resolved against the original (corresponding) element. For a <use>
nested within a <symbol>, this would mean that when were going to look
up the viewport element, we'd return the outer <symbol> element and thus
fail to get a viewport.
Use the instance element to setup the SVGLengthContext instead.

BUG=642524
Committed: https://crrev.com/b34ff6fe2d5842a63e2c66f68f050f0cf9163010
Cr-Commit-Position: refs/heads/master@{#415910}

[fs, 2016-08-31 16:25:57]

The CQ bit was checked by fs@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2016-08-31 16:26:17]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[fs, 2016-08-31 17:21:17]

fs@opera.com changed reviewers:
+ pdr@chromium.org

[commit-bot: I haz the power, 2016-08-31 18:25:40]

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

[commit-bot: I haz the power, 2016-08-31 18:25:40]

Dry run: This issue passed the CQ dry run.

[pdr., 2016-09-01 05:37:56]

LGTM

[fs, 2016-09-01 08:24:16]

The CQ bit was checked by fs@opera.com

[commit-bot: I haz the power, 2016-09-01 08:24:24]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-01 08:29:09]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-09-01 08:31:38]

Description was changed from

==========
Resolve percentage in <use> against the instance's viewport element

In LayoutSVGTransformableContainer::calculateLocalTransform, 'x' and 'y'
were resolved against the original (corresponding) element. For a <use>
nested within a <symbol>, this would mean that when were going to look
up the viewport element, we'd return the outer <symbol> element and thus
fail to get a viewport.
Use the instance element to setup the SVGLengthContext instead.

BUG=642524
==========

to

==========
Resolve percentage in <use> against the instance's viewport element

In LayoutSVGTransformableContainer::calculateLocalTransform, 'x' and 'y'
were resolved against the original (corresponding) element. For a <use>
nested within a <symbol>, this would mean that when were going to look
up the viewport element, we'd return the outer <symbol> element and thus
fail to get a viewport.
Use the instance element to setup the SVGLengthContext instead.

BUG=642524

Committed: https://crrev.com/b34ff6fe2d5842a63e2c66f68f050f0cf9163010
Cr-Commit-Position: refs/heads/master@{#415910}
==========

[commit-bot: I haz the power, 2016-09-01 08:31:39]

Patchset 1 (id:??) landed as
https://crrev.com/b34ff6fe2d5842a63e2c66f68f050f0cf9163010
Cr-Commit-Position: refs/heads/master@{#415910}