GitLab

Two steps:
1. moving chrome/browser/extensions/extension_omnibox* to a new directory chrome/browser/extensions/api/omnibox, along with dropping the prefix "extension_"
2. putting the classes, structs and functions from [extension_]omnibox_api.h to namespace extensions

BUG=125622
TEST=N/A


Review URL: http://codereview.chromium.org/10265022

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@134794 0039d316-1c4b-4281-b951-d872f2087c98