This CL makes it so that if a FocusChangeObserver deletes the focused window, we supply NULL as the |lost_focus| parameter to future FocusChangeObservers.
In particular, RenderWidgetHostViewAura::OnWindowFocused() sometimes deletes the window losing focus.

BUG=None
TEST=FocusControllerApiTest.DontPassDeletedWindow

Review URL: https://codereview.chromium.org/105143012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241939 0039d316-1c4b-4281-b951-d872f2087c98
Docserver: Recover from Blobstore errors in (new) GithubFileSystem by
re-fetching the entire blob.

BUG=318878
R=yoz@chromium.org

Review URL: https://codereview.chromium.org/117873002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241941 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241941