Allow chromedriver to install an extension and get all installed extension IDs.

chrome/test/functional/omnibox.py

Index: chrome/test/functional/omnibox.py
diff --git a/chrome/test/functional/omnibox.py b/chrome/test/functional/omnibox.py
index eee5af6a486a4ec419d74ef357ef80976b213086..db404ccdcec64de5e1265a3e1d975cb7573f4216 100644
--- a/chrome/test/functional/omnibox.py
+++ b/chrome/test/functional/omnibox.py
@@ -361,8 +361,7 @@ class OmniboxTest(pyauto.PyUITest):
     """
     app_crx_file = os.path.abspath(os.path.join(self.DataDir(),
                                    'pyauto_private', 'apps', app_name))
-    installed_app_id = self.InstallApp(app_crx_file)
-    self.assertTrue(installed_app_id, msg='App install failed.')
+    return self.InstallExtension(app_crx_file)
 
   def _VerifyOminiboxMatches(self, search_str, app_url, is_incognito):
     """Verify app matches in omnibox.