[Files.app] Show dot files in the Drive  volume.

Previously, the dot files were hidden by default and could be toggled.

This patch makes them visible only on Drive folder, since there are some temporary file in the Download directory and they should be hidden. 

BUG=196539
TEST=manually tested

Review URL: https://codereview.chromium.org/140893006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248153 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248153
aura: Remove event-dispatch methods from WindowTreeHostDelegate interface.

Update the aura::WindowTreeHost implementations to also be ui::EventSource, and
remove the event-dispatch related methods from the WindowTreeHostDelegate
interface. The implementation of the WindowTreeHostDelegate interface related to
event-dispatch in RootWindow uses ui::EventProcessor for dispatching events
anyway, and so it is a good time to remove this redundant code.

BUG=318879
R=ben@chromium.org

Review URL: https://codereview.chromium.org/147203004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248154 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248154