Mac AVFoundation:treat suspended cameras as unavailable

This CL is a relanding of the AVFoundation-related parts of
http://crrev.com/50133002/. The QTKit-related code was already
extracted and landed as http://crrev.com/55183002/.

The original description was:
>Treat suspended video capture devices on Mac as unavailable.
>
>This change
>1. removes suspended cameras from the list of device names,
>2. refuses to open suspended cameras,
>3. listens for suspend notifications to re-enumerate devices, and
>4. fixes a logic error in the mac device monitor (initial count was always zero).
>
>With this change, the internal camera on Mac OS will disappear
>from the device list when the lid is closed, and reappear when
>the lid is opened. "


BUG=288562, https://code.google.com/p/webrtc/issues/detail?id=1109

Review URL: https://codereview.chromium.org/182643003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253985 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253985
Add 9 patch scrollbar assets

Nine patch scrollbar is the design for overlay scroll for aura. This
patch adds assets, modifies ui resource files to include these assets.

BUG=307578

Review URL: https://codereview.chromium.org/183673003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253986 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253986