Use a scoped_ptr instead of a vector for released software frames.

This list always has a size of 0 or 1, so use a scoped_ptr instead of a
vector to represent it.

BUG=286038

Review URL: https://codereview.chromium.org/26259005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228623 0039d316-1c4b-4281-b951-d872f2087c98
Files.app: Create the search box class.

Originally the search box UI is complicated but there is no class to manage it.
This CL adds the search box class to manage the UI.

BUG=306356
TEST=manually

Review URL: https://codereview.chromium.org/26486006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228624 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228623
SVN changes up to revision 228624