Make nesting/running states a RunLoop rather than a MessageLoop concept.

mash/quick_launch/quick_launch.cc

Index: mash/quick_launch/quick_launch.cc
diff --git a/mash/quick_launch/quick_launch.cc b/mash/quick_launch/quick_launch.cc
index df88763a4c1b512a087311a94146a563e4665142..eaef8203ef16ac1425857ab0cf8f219aa628d4ed 100644
--- a/mash/quick_launch/quick_launch.cc
+++ b/mash/quick_launch/quick_launch.cc
@@ -7,6 +7,7 @@
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
@@ -166,7 +167,7 @@ void QuickLaunch::RemoveWindow(views::Widget* window) {
   auto it = std::find(windows_.begin(), windows_.end(), window);
   DCHECK(it != windows_.end());
   windows_.erase(it);
-  if (windows_.empty() && base::MessageLoop::current()->is_running())
+  if (windows_.empty() && base::RunLoop::IsRunningOnCurrentThread())
     base::MessageLoop::current()->QuitWhenIdle();
 }