Move actions after browser Start in cros_browser_backend.Start to DidStart.

BUG=398467
NOTRY=true
NOTREECHECKS=true

Review URL: https://codereview.chromium.org/499453002

Cr-Commit-Position: refs/heads/master@{#291310}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@291310 0039d316-1c4b-4281-b951-d872f2087c98

tools/telemetry/telemetry/core/backends/chrome/cros_browser_backend.py

@@ -136,7 +136,10 @@ class CrOSBrowserBackend(chrome_browser_backend.ChromeBrowserBackend):
     # Wait for oobe.
     self._WaitForBrowserToComeUp(wait_for_extensions=False)
     util.WaitFor(lambda: self.oobe_exists, 10)
+    logging.info('Browser is up!')
 
+  def DidStart(self):
+    super(CrOSBrowserBackend, self).DidStart()
     if self.browser_options.auto_login:
       try:
         if self._is_guest:
@@ -154,7 +157,6 @@ class CrOSBrowserBackend(chrome_browser_backend.ChromeBrowserBackend):
         self._cri.TakeScreenShot('login-screen')
         raise exceptions.LoginException('Timed out going through login screen')
 
-    logging.info('Browser is up!')
 
   def Close(self):
     super(CrOSBrowserBackend, self).Close()