Guard Element and getComputedStyle methods that force a layout with inActiveDocument.

Guard Element and getComputedStyle methods that force a layout with inActiveDocument.

This patch makes touching an Element property that would normally force
a layout not do it when the element is not in the document since the
layout of the document has no impact on the element. I also fixed
getComputedStyle.

Note that this patch does not attempt to fix subclasses of Element, for
example some canvas properties may force layouts still. This just fixes
the core dom Element API, which is most of the usage I found.

I added stack traces and observed forced layouts from getting innerText
on google image search, getBoundingClient rect in most polymer apps,
and offsetTop on various news sites like the NYT. This patch removes
all of these forced layouts.

BUG=585663
Committed: https://crrev.com/f6ae8a23e7de1a6199c1deeaef9041f9cc7caab9
Cr-Commit-Position: refs/heads/master@{#383928}

[esprehn, 2016-03-30 00:36:02]

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

[commit-bot: I haz the power, 2016-03-30 00:36:35]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1839803007/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1839803007/1

[esprehn, 2016-03-30 01:05:08]

esprehn@chromium.org changed reviewers:
+ dglazkov@chromium.org, ojan@chromium.org

[ojan, 2016-03-30 01:10:47]

lgtm

https://codereview.chromium.org/1839803007/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/css/CSSComputedStyleDeclaration.cpp (right):

https://codereview.chromium.org/1839803007/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/css/CSSComputedStyleDeclaration.cpp:570:
styledNode = this->styledNode();
Not relevant to this patch, but this line could use an explanatory comment for
why it's needed.

[esprehn, 2016-03-30 02:13:19]

Description was changed from

==========
Guard Element and getComputedStyle methods that force a layout with
inActiveDocument.

This patch makes touching an Element property that would normally force
a layout not do it when the element is not in the document since the
layout of the document has no impact on the element. I also fixed
getComputedStyle.

Note that this patch does not attempt to fix subclasses of Element, for
example some canvas properties may force layouts still. This just fixes
the core dom Element API, which is most of the usage I found.

I added stack traces and observed forced layouts from setting innerText
on google image search, getBoundingClient rect in most polymer apps,
and offsetTop on various news sites like the NYT. This patch removes
all of these forced layouts.

BUG=585663
==========

to

==========
Guard Element and getComputedStyle methods that force a layout with
inActiveDocument.

This patch makes touching an Element property that would normally force
a layout not do it when the element is not in the document since the
layout of the document has no impact on the element. I also fixed
getComputedStyle.

Note that this patch does not attempt to fix subclasses of Element, for
example some canvas properties may force layouts still. This just fixes
the core dom Element API, which is most of the usage I found.

I added stack traces and observed forced layouts from getting innerText
on google image search, getBoundingClient rect in most polymer apps,
and offsetTop on various news sites like the NYT. This patch removes
all of these forced layouts.

BUG=585663
==========

[esprehn, 2016-03-30 03:05:30]

The CQ bit was unchecked by esprehn@chromium.org

[esprehn, 2016-03-30 03:05:33]

The CQ bit was checked by esprehn@chromium.org

[commit-bot: I haz the power, 2016-03-30 03:05:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1839803007/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1839803007/1

[commit-bot: I haz the power, 2016-03-30 06:46:46]

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

[commit-bot: I haz the power, 2016-03-30 06:46:47]

Try jobs failed on following builders:
  win_chromium_rel_ng on tryserver.chromium.win (JOB_TIMED_OUT,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)
  win_chromium_x64_rel_ng on tryserver.chromium.win (JOB_TIMED_OUT,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[esprehn, 2016-03-30 06:50:15]

The CQ bit was checked by esprehn@chromium.org

[commit-bot: I haz the power, 2016-03-30 06:50:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1839803007/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1839803007/1

[commit-bot: I haz the power, 2016-03-30 08:11:58]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-03-30 08:12:54]

Description was changed from

==========
Guard Element and getComputedStyle methods that force a layout with
inActiveDocument.

This patch makes touching an Element property that would normally force
a layout not do it when the element is not in the document since the
layout of the document has no impact on the element. I also fixed
getComputedStyle.

Note that this patch does not attempt to fix subclasses of Element, for
example some canvas properties may force layouts still. This just fixes
the core dom Element API, which is most of the usage I found.

I added stack traces and observed forced layouts from getting innerText
on google image search, getBoundingClient rect in most polymer apps,
and offsetTop on various news sites like the NYT. This patch removes
all of these forced layouts.

BUG=585663
==========

to

==========
Guard Element and getComputedStyle methods that force a layout with
inActiveDocument.

This patch makes touching an Element property that would normally force
a layout not do it when the element is not in the document since the
layout of the document has no impact on the element. I also fixed
getComputedStyle.

Note that this patch does not attempt to fix subclasses of Element, for
example some canvas properties may force layouts still. This just fixes
the core dom Element API, which is most of the usage I found.

I added stack traces and observed forced layouts from getting innerText
on google image search, getBoundingClient rect in most polymer apps,
and offsetTop on various news sites like the NYT. This patch removes
all of these forced layouts.

BUG=585663

Committed: https://crrev.com/f6ae8a23e7de1a6199c1deeaef9041f9cc7caab9
Cr-Commit-Position: refs/heads/master@{#383928}
==========

[commit-bot: I haz the power, 2016-03-30 08:12:55]

Patchset 1 (id:??) landed as
https://crrev.com/f6ae8a23e7de1a6199c1deeaef9041f9cc7caab9
Cr-Commit-Position: refs/heads/master@{#383928}