Move cryptohome methods to CrosInterface.

* CryptohomePath and IsCryptohomeMounted moved to CrosInterface
* Move _GetLoginStatus and _IsCryptohomeMounted closer to where they are used.
BUG=308757
TEST=manual
NOTRY=True

Review URL: https://codereview.chromium.org/189953002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256394 0039d316-1c4b-4281-b951-d872f2087c98
Fix api_level check.

Currently broken because the CheckSDKPlatform expects an integer.

BUG=344622, 344622
TBR=bulach@chromium.org

Review URL: https://codereview.chromium.org/195363004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256395 0039d316-1c4b-4281-b951-d872f2087c98
Add views implementation for AXTreeSource.

Note that this cl required fixing PanelView (chrome/browser/ui/views/panels). It neglected to remove its observers previously leading to av's when attempting to notify observers from |Widget|.


BUG=318758

Review URL: https://codereview.chromium.org/173893003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@256396 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 256396