Add TRACE_EVENTs for MSE playback on Android.

BUG=none
TEST=none

Review URL: https://codereview.chromium.org/25751002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226915 0039d316-1c4b-4281-b951-d872f2087c98
Move construction of the AlternateNavURLFetcher from the LocationBar subclasses
to the OmniboxEditModel.

BUG=151044
TEST=none
R=sky@chromium.org

Review URL: https://codereview.chromium.org/25869004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226916 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226916