Abort the animation in PanelStackView when one stacked panel is gone.

This is to fix potential crash in PanelStackView::UpdatePanelsBounds.
We need to abort the ongoing animation when one panel in the stack is
removed.

BUG=290983
TEST=existing tests
R=petewil@chromium.org

Review URL: https://codereview.chromium.org/23449049

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224795 0039d316-1c4b-4281-b951-d872f2087c98
Revert special handling of GDK_MOD5_MASK.

As part of migrating the InputEventBuilders from Blink into
Chromium, crrev.com/23815005 also introduced code to set the
Ctrl + Alt modifiers when GDK_MOD5_MASK (AltGr) was present.
However, this breaks AltGr handling on (at least) French
keyboard layouts by preventing the alternate-graphic characters
from being handled correctly.

From the end-user perspective, they can no longer enter these
characters.

This cl removes the special GDK_MOD5_MASK handling to fix the
problem (reverting to the previous behavior).

BUG=263189
R=jdduke@chromium.org

Review URL: https://codereview.chromium.org/23498051

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224796 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 224796
Add VideoDecoderSelector::Abort().

This is useful to cancel the video decoder selection process when a video
decoder or the DecryptingDemuxerStream is waiting for initialization to be
completed.

BUG=222054,chrome-os-partner:22518
TEST=Added unittest to cover this.
R=scherkus@chromium.org

Review URL: https://codereview.chromium.org/23849007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224798 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 224798