Fixes crasher when closing app windows while printing.

The ShellWindow acts as the delegate of a WebContentsModalDialogManager
for modal panels like the print preview panel. This change clears this
delegation relationship when the ShellWindow is closed by the user,
preventing a crash caused by the WebContentsModalDialogManager accessing
its ShellWindow delegate after ~ShellWindow is called.

There is a manual test case for the crasher in the bug report.

BUG=297179

Review URL: https://codereview.chromium.org/24363008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225484 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225484
drive: Skip applying root entry in feeds.

We expected the "My Drive" (or drive/root) entry is NOT included in the
feeds from the server. However, in some occasion (maybe a server side bug),
it is included. To be defensive we should filter our such an entry here.

BUG=297259

Review URL: https://codereview.chromium.org/24500004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225485 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225485
Fix test timeout on a failed virtual keyboard test.

BUG=229691
R=bshe@chromium.org

Review URL: https://codereview.chromium.org/23609066

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225486 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225486