Add base::RunLoop and update ui_test_utils to use it to reduce flakiness

content/browser/browser_main_loop.cc

Index: content/browser/browser_main_loop.cc
diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index d2021111c6f77d91b1730a56e758d6b985f0abe5..292bc3b13cccac09da5385d2a6af60c7fe744b04 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -12,6 +12,7 @@
 #include "base/message_loop.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
+#include "base/run_loop.h"
 #include "base/string_number_conversions.h"
 #include "base/threading/thread_restrictions.h"
 #include "content/browser/browser_thread_impl.h"
@@ -648,16 +649,16 @@ void BrowserMainLoop::InitializeToolkit() {
 }
 
 void BrowserMainLoop::MainMessageLoopRun() {
+  DCHECK_EQ(MessageLoop::TYPE_UI, MessageLoop::current()->type());
   if (parameters_.ui_task)
     MessageLoopForUI::current()->PostTask(FROM_HERE, *parameters_.ui_task);
 
-#if defined(OS_MACOSX)
-  MessageLoopForUI::current()->Run();
-#elif defined(OS_ANDROID)
+#if defined(OS_ANDROID)
   // Android's main message loop is the Java message loop.
   NOTREACHED();
 #else

[jar (doing other things), 2012/06/23 02:43:19]

Can you move lines 652-654 into this #else clause?  It probably should have
closer to that in the past (no code in Android flavor).

[jbates, 2012/06/25 20:04:57]

Done.

-  MessageLoopForUI::current()->RunWithDispatcher(NULL);
+  base::RunLoop run_loop;
+  run_loop.Run();
 #endif
 }