Reland r59641. Add the onBeforeNavigate and onErrorOccured events to the webNavigation API.

Also, rewrite the onCommitted event such that AUTO_SUBFRAME events are also registered.

BUG=50943
TEST=WebNavigationEvents

Review URL: http://codereview.chromium.org/3383008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@59777 0039d316-1c4b-4281-b951-d872f2087c98
7 files changed