Adds unit tests for modifier keys.


BUG=311666

Review URL: https://codereview.chromium.org/54783002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232307 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232307
sync: add ProcessSyncChanges to SessionsSyncManager.

BUG=98892

Review URL: https://codereview.chromium.org/33023004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232308 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232308