Remove remaining calls to deprecated MessageLoop methods.

mojo/public/cpp/bindings/tests/request_response_unittest.cc

Index: mojo/public/cpp/bindings/tests/request_response_unittest.cc
diff --git a/mojo/public/cpp/bindings/tests/request_response_unittest.cc b/mojo/public/cpp/bindings/tests/request_response_unittest.cc
index 2007ad76e072f70a3c29d0e845bfb17f6e44b761..3c024ade7fc6d9c0ba07df8963e76ca5a191952d 100644
--- a/mojo/public/cpp/bindings/tests/request_response_unittest.cc
+++ b/mojo/public/cpp/bindings/tests/request_response_unittest.cc
@@ -85,9 +85,9 @@ void RecordEnum(sample::Enum* storage,
 class RequestResponseTest : public testing::Test {
  public:
   RequestResponseTest() {}
-  ~RequestResponseTest() override { loop_.RunUntilIdle(); }
+  ~RequestResponseTest() override { base::RunLoop().RunUntilIdle(); }
 
-  void PumpMessages() { loop_.RunUntilIdle(); }
+  void PumpMessages() { base::RunLoop().RunUntilIdle(); }
 
  private:
   base::MessageLoop loop_;