Revert 156744 - chromeos: Use EventRouterForwarder to disptch systemPrivate extension events

Reason: Seem to be causing ExtensionServiceTest unit_tests timeout
on "Linux ChromiumOS Tests (1)". See crbug.com/149157 for details.  


BUG=148552
TEST=Boot a Chromebook, type the password for a user, start pressing brightness up/down key randomly, press Enter to login while keeping pressing brightness keys, ensure no crash report is sent during login.


Review URL: https://chromiumcodereview.appspot.com/10905250

TBR=hashimoto@chromium.org
Review URL: https://codereview.chromium.org/10919299

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@156865 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed