Implement Browser Actions extensions.

Browser Actions are like Page Actions, except they appear next to the Omnibox and are always visible. For details see http://code.google.com/p/chromium/wiki/BrowserActions.

Added a simple browser action sample that adds a Print button to the chrome toolbar (which brings up the Print dialog for the current page).

Removed |type| from PageActions, which is currently ignored and was already removed from the docs.

Each extension can only have 1 browser_action. Each browser action can specify more than one icon, but only the first is used. And no API has been added yet (besides the event definition).

BUG=22099
TEST=Install the sample browser action, navigate to google.com, press the print button. A print dialog should come up.
Review URL: http://codereview.chromium.org/243001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@27319 0039d316-1c4b-4281-b951-d872f2087c98
30 files changed