Copy build changes to compile mojo::AsyncWaiter to the chromium repo.

mojo/environment/default_run_loop_impl.cc

Index: mojo/environment/default_run_loop_impl.cc
diff --git a/mojo/environment/default_run_loop_impl.cc b/mojo/environment/default_run_loop_impl.cc
index 07037b73430f1ce8619df0b2f4592166f488c411..4fa9ffd1f46574b2b593acdf53336ff9fea9e217 100644
--- a/mojo/environment/default_run_loop_impl.cc
+++ b/mojo/environment/default_run_loop_impl.cc
@@ -11,12 +11,16 @@ namespace mojo {
 namespace internal {
 
 void InstantiateDefaultRunLoopImpl() {
+  CHECK(!base::MessageLoop::current());
   // Not leaked: accessible from |base::MessageLoop::current()|.
-  new base::MessageLoop();
+  base::MessageLoop* message_loop = new base::MessageLoop();
+  CHECK_EQ(message_loop, base::MessageLoop::current());
 }
 
 void DestroyDefaultRunLoopImpl() {
+  CHECK(base::MessageLoop::current());
   delete base::MessageLoop::current();
+  CHECK(!base::MessageLoop::current());
 }
 
 }  // namespace internal