Support reordering of Browser Actions within the container. Currently does not support dragging to/from the chevron menu.

Also fixed two bugs in the same code:
- the container would be 0 width if a value for it hasn't been saved (part of bug 32101).
- the default icon was not used when a tab specific icon was not found (bug 34317).

BUG=http://crbug.com/26990, http://crbug.com/32101, http://crbug.com/34317
TEST=In both LTR and RTL locale, try reordering the browser actions and make sure to test dragging to the ends with and without a chevron visible. Install Send to Gmail extension and make sure it has an icon while in the overflow menu.
Review URL: http://codereview.chromium.org/549224

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@37922 0039d316-1c4b-4281-b951-d872f2087c98
13 files changed