Hovered/active/focused nodes will never share style with siblings/cousins.

Hovered/active/focused nodes will never share style with siblings/cousins.

For any given hovered/active node at a given time, other hovered/active nodes
are either ancestors or descendants of that node. Since style sharing is
looking at siblings and cousins, hovered/active nodes will never share style.

Similarly, there's always a single focused element in a document, hence it
will never share style with another node.

This change bails out early for style sharing in those cases.

BUG=255189
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=153529

[rune, 2013-06-27 21:44:18]

Not sure if the added performance test is the most suitable, but it shows the
improvement with this fix.

[rune, 2013-07-02 07:49:55]

https://codereview.chromium.org/18089009/diff/1/PerformanceTests/CSS/HoverUpd...
File PerformanceTests/CSS/HoverUpdate.html (right):

https://codereview.chromium.org/18089009/diff/1/PerformanceTests/CSS/HoverUpd...
PerformanceTests/CSS/HoverUpdate.html:27: var d2 =
document.getElementById("d2");
Unused d1/d2 left-overs from earlier iteration of the test.

[rune, 2013-07-02 08:28:12]

> Unused d1/d2 left-overs from earlier iteration of the test.

Removed in Patch Set 3.

[rune, 2013-07-03 08:31:07]

Added potential reviewers.

[eae, 2013-07-03 18:13:37]

LGTM, thanks!

[commit-bot: I haz the power, 2013-07-03 18:25:50]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rune@opera.com/18089009/7002

[commit-bot: I haz the power, 2013-07-03 19:27:57]

Retried try job too often on linux_layout_rel for step(s) webkit_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_layo...

[commit-bot: I haz the power, 2013-07-03 19:43:57]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rune@opera.com/18089009/7002

[commit-bot: I haz the power, 2013-07-03 22:02:03]

Change committed as 153529

[rune, 2013-07-05 12:29:47]

On 2013/07/03 22:02:03, I haz the power (commit-bot) wrote:
> Change committed as 153529

Was reverted because performance test relied on a dom object only available with
the WebKit performance framework (WebKit/Tools/Scripts/run-perf-tests).

New attempt, testing :focus this time:

https://codereview.chromium.org/18764003