chromeos: Fix shelf appearing at login screen under mash

chrome/browser/chromeos/login/session/chrome_session_manager.cc

Index: chrome/browser/chromeos/login/session/chrome_session_manager.cc
diff --git a/chrome/browser/chromeos/login/session/chrome_session_manager.cc b/chrome/browser/chromeos/login/session/chrome_session_manager.cc
index 466133dfe07f97373a7f2367457293c2f7e40463..54514ca0119f754ec9d4d3a722208580e715bf99 100644
--- a/chrome/browser/chromeos/login/session/chrome_session_manager.cc
+++ b/chrome/browser/chromeos/login/session/chrome_session_manager.cc
@@ -26,6 +26,7 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/signin/signin_manager_factory.h"
 #include "chrome/browser/ui/ash/ash_util.h"
+#include "chrome/browser/ui/ash/session_controller_client.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chromeos/audio/cras_audio_handler.h"
@@ -133,8 +134,12 @@ void StartRestoreAfterCrashSession(Profile* user_profile,
 
   bool is_running_test = command_line->HasSwitch(::switches::kTestName) ||
                          command_line->HasSwitch(::switches::kTestType);
-
-  if (!is_running_test) {
+  if (is_running_test) {
+    // Some browser tests (e.g. BrowserTest.GetSizeForNewRenderView) require
+    // that ash is synchronously initialized before the first test window opens.
+    // Ensure the session-related mojo messages are sent to ash.
+    SessionControllerClient::FlushForTesting();

[James Cook, 2016/12/16 01:28:27]

xiyuan, this seemed better than just pumping the message loop. I added a
g_instance to SessionControllerClient because there's no simple way to access it
via ChromeBrowserMainExtraPartsAsh.

Eventually ChromeBrowserMainExtraPartsAsh should become part of
ChromeBrowserMainPartsChromeOS, but that's a much bigger change than I can do in
this CL.

+  } else {
     // Enable CrasAudioHandler logging when chrome restarts after crashing.
     if (chromeos::CrasAudioHandler::IsInitialized())
       chromeos::CrasAudioHandler::Get()->LogErrors();