Files.app: Treat zip archives correctly as readonly.

The mounted zip archives volume info does not come as the "Disk"
structure that represents a physical device-ish stuff.
We should specially treat the archive case by inspecting the
mount type, as we were doing in JS side before the regression in M33.

BUG=336355

Review URL: https://codereview.chromium.org/132393006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246499 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246499
[Hotword] Putting preferences under search for hotword service. Putting behind a flag.

In order to test/see the new settings run chrome with "--force-fieldtrials=VoiceTrigger/abc/

BUG=325439,289023

Review URL: https://codereview.chromium.org/134103005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@246500 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 246500