Long press menu (shift+f6) to toggle spoken feedback.
 Factor out KeyHoldDetector.

BUG=343277
TEST=SpokenFeedbackTogglerTest

Review URL: https://codereview.chromium.org/164823005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251490 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251490
Media Galleries: Remove apps that have switched off from mediaGalleriesPrivate from the whitelist.

BUG=144496,286542

Review URL: https://codereview.chromium.org/165263006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251491 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251491
Shorter timeout to auto-launch from the voice search.

BUG=None
R=xiyuan@chromium.org
TEST=manually

Review URL: https://codereview.chromium.org/167413002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251492 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251492