Main frame should remain scrollable if the fullscreen element is the document

Main frame should remain scrollable if the fullscreen element is the document

In a previous CL we disabled main frame impl-side scrolling if there is a
fullscreen element because the fullscreen element can balloon up scroll events
to the (invisible) main frame layer and cause weird artifacts.

However if the element that enter fullscreen is the main frame document itself,
we should allow it remain scrollable.

BUG=376699
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=175089

[trchen, 2014-05-29 00:15:18]

Context: https://codereview.chromium.org/200943002/

Test coming soon.

[aelias_OOO_until_Jul13, 2014-05-29 00:18:41]

lgtm

[trchen, 2014-05-29 00:42:14]

Test added. PTAL, thanks!

[aelias_OOO_until_Jul13, 2014-05-29 02:58:34]

lgtm, still needs OWNERS approval for Source/core

[Hajime Morrita, 2014-05-29 20:00:23]

lgtm. 

Just for curious, what about other browsers? IIRC the fullscreen API is
supported by Firefox as well.
Generally it is nice to align these kind of behaviors to others.

[trchen, 2014-05-29 21:01:39]

On 2014/05/29 20:00:23, morrita wrote:
> lgtm. 
> 
> Just for curious, what about other browsers? IIRC the fullscreen API is
> supported by Firefox as well.
> Generally it is nice to align these kind of behaviors to others.

I'm sure that if the element that entered fullscreen has an overflow and has
overflow:scroll or auto, it will still be scrollable in fullscreen. What I don't
know is if they also prevent event ballooning up to the main frame. (IMO they
shouldn't, right?)

[trchen, 2014-05-29 21:01:45]

The CQ bit was checked by trchen@chromium.org

[commit-bot: I haz the power, 2014-05-29 21:02:49]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/trchen@chromium.org/305833002/20001

[trchen, 2014-05-29 21:03:45]

On 2014/05/29 21:01:39, trchen wrote:
> On 2014/05/29 20:00:23, morrita wrote:
> > lgtm. 
> > 
> > Just for curious, what about other browsers? IIRC the fullscreen API is
> > supported by Firefox as well.
> > Generally it is nice to align these kind of behaviors to others.
> 
> I'm sure that if the element that entered fullscreen has an overflow and has
> overflow:scroll or auto, it will still be scrollable in fullscreen. What I
don't
> know is if they also prevent event ballooning up to the main frame. (IMO they
> shouldn't, right?)

Oops, I mean they (the events) shouldn't (balloon up), i.e., they should prevent
event from ballooning up.

[commit-bot: I haz the power, 2014-05-29 22:39:59]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  linux_blink_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_dbg/builds/1...)

[commit-bot: I haz the power, 2014-05-30 00:58:43]

Change committed as 175089