Make text track and cue wrapper objects dependent on their media element.

If a TextTrack or VTTCue (TextTrackCue) object is added to a media
element, indirectly by way of addCue() or addTextTrack(), arrange for
their wrapper objects to be registered as dependents  of the media
element's wrapper so as to keep these wrapper objects alive.

This is done so that when we later need to return back a wrapper
for the underlying track/cue object, the same wrapper object is returned.

R=acolwell@chromium.org
BUG=358109

Review URL: https://codereview.chromium.org/242113012

git-svn-id: svn://svn.chromium.org/blink/trunk@172065 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove m_forcedCompositingMode from RenderLayerCompositor.

We don't need this bit anymore. m_compositing serves it's purpose,
except in CompositingRequirementsUpdater::updateRecursive, where
we can just query the setting directly as needed.

RenderLayerCompositor::updateIfNeeded would unecessarily
do all it's work and then disabled compositing if hasAcceleratedCompositing
returned false. Instead, we can early return. As far as I
know this only affects SVGImages at the moment, but there
should be no change in behavior.

Review URL: https://codereview.chromium.org/242383002

git-svn-id: svn://svn.chromium.org/blink/trunk@172066 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Prevent quirks mode for srcdoc iframe document

This change locks document mode for srcdoc-made iframe document.
This matches latest HTML standard and Firefox.

R=abarth
TEST~=srcdoc-cannot-be-in-quirks-mode.html
BUG=365005

Review URL: https://codereview.chromium.org/243413005

git-svn-id: svn://svn.chromium.org/blink/trunk@172068 bbb929c8-8fbe-4397-9dbb-9b2b20218538
KURL::isBlankURL should not include about:srcdoc

Rename isBlankURL to isProtocolAbout to match isPrococolData
and hopefully make callers less confused.

This is in preparation for making about:srcdoc not go
through the main-thread parser.

BUG=309862
R=abarth@chromium.org

Review URL: https://codereview.chromium.org/245413002

git-svn-id: svn://svn.chromium.org/blink/trunk@172069 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Auto-rebaseline for r172042

http://src.chromium.org/viewvc/blink?view=revision&revision=172042

BUG=360524
TBR=jchaffraix@chromium.org

Review URL: https://codereview.chromium.org/245623004

git-svn-id: svn://svn.chromium.org/blink/trunk@172070 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Mark compositing/images/direct-pdf-image.html as flaky on Mac

TBR=tony@chromium.org
BUG=365400

Review URL: https://codereview.chromium.org/243583009

git-svn-id: svn://svn.chromium.org/blink/trunk@172071 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Auto-rebaseline for r172041

http://src.chromium.org/viewvc/blink?view=revision&revision=172041

BUG=249354
TBR=vollick@chromium.org

Review URL: https://codereview.chromium.org/245053005

git-svn-id: svn://svn.chromium.org/blink/trunk@172072 bbb929c8-8fbe-4397-9dbb-9b2b20218538