Respect the window list order returned from webrtc::WindowCapturer.
So the window picker will show the windows by the z-order.

BUG=https://code.google.com/p/webrtc/issues/detail?id=2840

Review URL: https://codereview.chromium.org/143283008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250153 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250153
Use posix version of stack_trace on iOS

The iOS specific version was not async-safe, and the posix version
works correctly on iOS (manually tested). Scrap the iOS version
and always use the posix one.

BUG=334640
R=mark@chromium.org

Review URL: https://codereview.chromium.org/136033004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250154 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250154