Reorder function definitions to match declarations.  No code change.

Also eliminates one GTK declaration that is never defined, and minorly adjusts
the GTK OmniboxEditController override order to match the base class.

BUG=none
TEST=none
TBR=erg

Review URL: https://codereview.chromium.org/25687008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226566 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226566