Let toParentMediaElement return null for the media element itself

Let toParentMediaElement return null for the media element itself

An element isn't its own parent, and actual usage doesn't require it.

TEST=LayoutTests/media/video-webkit-appearance.html

Without the fix, this test hits the ASSERT_WITH_SECURITY_IMPLICATION
in mediaControlElementType(), via paintMediaPlayButton().

BUG=414100
R=fs@opera.com

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=182664

[fs, 2014-09-24 15:48:16]

https://codereview.chromium.org/598013002/diff/1/Source/core/html/shadow/Medi...
File Source/core/html/shadow/MediaControlElementTypes.cpp (right):

https://codereview.chromium.org/598013002/diff/1/Source/core/html/shadow/Medi...
Source/core/html/shadow/MediaControlElementTypes.cpp:54: return 0;
paintMediaSliderThumb and paintMediaVolumeSliderThumb both seem to pass
renderer->node()->shadowHost() as node - which seems strange to me. It seems
that could/would trigger this code-path as well?

[philipj_slow, 2014-09-25 07:53:10]

https://codereview.chromium.org/598013002/diff/1/Source/core/html/shadow/Medi...
File Source/core/html/shadow/MediaControlElementTypes.cpp (right):

https://codereview.chromium.org/598013002/diff/1/Source/core/html/shadow/Medi...
Source/core/html/shadow/MediaControlElementTypes.cpp:54: return 0;
On 2014/09/24 15:48:16, fs wrote:
> paintMediaSliderThumb and paintMediaVolumeSliderThumb both seem to pass
> renderer->node()->shadowHost() as node - which seems strange to me. It seems
> that could/would trigger this code-path as well?

They pass renderer->node()->shadowHost() because the sliders are themselves
implemented using shadow DOM. It all seems to work at least, and if one uses
toParentMediaElement(object->node()->shadowHost()) e.g. in
paintMediaPlayButton() that button fails to be painted.

[fs, 2014-09-25 09:30:19]

https://codereview.chromium.org/598013002/diff/1/Source/core/html/shadow/Medi...
File Source/core/html/shadow/MediaControlElementTypes.cpp (right):

https://codereview.chromium.org/598013002/diff/1/Source/core/html/shadow/Medi...
Source/core/html/shadow/MediaControlElementTypes.cpp:54: return 0;
On 2014/09/25 07:53:10, philipj wrote:
> On 2014/09/24 15:48:16, fs wrote:
> > paintMediaSliderThumb and paintMediaVolumeSliderThumb both seem to pass
> > renderer->node()->shadowHost() as node - which seems strange to me. It seems
> > that could/would trigger this code-path as well?
> 
> They pass renderer->node()->shadowHost() because the sliders are themselves
> implemented using shadow DOM. It all seems to work at least, and if one uses
> toParentMediaElement(object->node()->shadowHost()) e.g. in
> paintMediaPlayButton() that button fails to be painted.

Ok, I figured it'd be something like that. LGTM.

[philipj_slow, 2014-09-25 09:38:09]

The CQ bit was checked by philipj@opera.com

[commit-bot: I haz the power, 2014-09-25 09:38:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/598013002/1

[commit-bot: I haz the power, 2014-09-25 09:43:22]

Committed patchset #1 (id:1) as 182664