Optimize (slightly) Document::updateHoverActiveState.

Optimize (slightly) Document::updateHoverActiveState.

When walking up the chain of potentially effected elements, we can stop
updating hover state as soon as we hit the common ancestor of the newly
hovered element and the previously hovered element. This is a tiny
optimization; it should result in no web-visible change in behavior.

This patch is extracted from the larger mouseenter/mouseleave WebKit
patch[1] submitted by allan.jensen@digia.com (carewolf), reviewed by
David Hyatt.

[1]: http://trac.webkit.org/changeset/149173,

BUG=236215
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=153664

[Mike West, 2013-06-30 18:03:44]

Hey Jochen, mind taking a look at this? I'm splitting carewolf's
mouseenter/mouseleave WebKit patch (linked in the description) into smaller
chunks; this is the first.

CCing Eric, Ojan, and Elliott, as they'd expressed interest in the patch way
back in April when I thought I'd found a new contributor for whom the patch
would have been a GoodFirstBug. :( This bit seems uncontroversial, but I think
there will be some shadow DOM bits in the next patch where I'll likely miss
something.

-mike

[jochen (gone - plz use gerrit), 2013-07-01 09:13:29]

lgtm

[commit-bot: I haz the power, 2013-07-01 14:11:35]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/mkwst@chromium.org/18297002/1

[commit-bot: I haz the power, 2013-07-01 16:03:58]

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

[commit-bot: I haz the power, 2013-07-01 16:51:08]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/mkwst@chromium.org/18297002/1

[commit-bot: I haz the power, 2013-07-01 19:06:00]

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

[Mike West, 2013-07-02 11:55:40]

On 2013/07/01 19:06:00, I haz the power (commit-bot) wrote:
> Retried try job too often on win_layout_rel for step(s) webkit_tests
>
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_layout...

drag-select-1.html looks like it's consistently failing on Windows only, which
is awesome. i'll have to take a look at it when i'm back in the office in a week
or two.

[Mike West, 2013-07-08 08:20:16]

On 2013/07/02 11:55:40, Mike West (on paternity leave) wrote:
> On 2013/07/01 19:06:00, I haz the power (commit-bot) wrote:
> > Retried try job too often on win_layout_rel for step(s) webkit_tests
> >
>
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_layout...
> 
> drag-select-1.html looks like it's consistently failing on Windows only, which
> is awesome. i'll have to take a look at it when i'm back in the office in a
week
> or two.

Looks like it just needs a trivial rebaseline. I'll use Ojan's amazing new bot!

[commit-bot: I haz the power, 2013-07-08 08:34:15]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/mkwst@chromium.org/18297002/21001

[commit-bot: I haz the power, 2013-07-08 09:52:29]

Change committed as 153664

[ojan, 2013-07-08 21:10:06]

On 2013/07/08 08:20:16, Mike West (on paternity leave) wrote:
> On 2013/07/02 11:55:40, Mike West (on paternity leave) wrote:
> > On 2013/07/01 19:06:00, I haz the power (commit-bot) wrote:
> > > Retried try job too often on win_layout_rel for step(s) webkit_tests
> > >
> >
>
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_layout...
> > 
> > drag-select-1.html looks like it's consistently failing on Windows only,
which
> > is awesome. i'll have to take a look at it when i'm back in the office in a
> week
> > or two.
> 
> Looks like it just needs a trivial rebaseline. I'll use Ojan's amazing new
bot!

w00t! https://codereview.chromium.org/18801010/