Move ui_test_utils::RunMessageLoop to test_utils so that it can be reused by content_browsertests.

BUG=90448
Review URL: https://chromiumcodereview.appspot.com/10822030

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@148514 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/app_process_apitest.cc b/chrome/browser/extensions/app_process_apitest.cc
index cc73033a..61170fc 100644
--- a/chrome/browser/extensions/app_process_apitest.cc
+++ b/chrome/browser/extensions/app_process_apitest.cc
@@ -495,7 +495,7 @@
 
   // Wait for app tab to be created and loaded.
   test_navigation_observer.WaitForObservation(
-      base::Bind(&ui_test_utils::RunMessageLoop),
+      base::Bind(&content::RunMessageLoop),
       base::Bind(&MessageLoop::Quit,
                  base::Unretained(MessageLoopForUI::current())));