Reland r54723. Implement the webNavigation.onCommitted event.

BUG=50943
TEST=ExtensionApiTest.WebNavigationEvents

Review URL: http://codereview.chromium.org/3310025

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@59212 0039d316-1c4b-4281-b951-d872f2087c98
21 files changed