Add FlushForTesting to InterfacePtr and Binding.

mojo/public/cpp/bindings/binding.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_BINDING_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_BINDING_H_
 
 #include <utility>
 
 #include "base/callback_forward.h"
@@ skipping 230 matching lines @@
   MessagePipeHandle handle() const { return internal_state_.handle(); }
 
   // Returns the associated group that this object belongs to. Returns null if:
   //   - this object is not bound; or
   //   - the interface doesn't have methods to pass associated interface
   //     pointers or requests.
   AssociatedGroup* associated_group() {
     return internal_state_.associated_group();
   }
 
+  // Sends a no-op message on the underlying message pipe and runs the current
+  // message loop until its response is received. This can be used in tests to
+  // verify that no message was sent on a message pipe in response to some
+  // stimulus.
+  void FlushForTesting() { internal_state_.FlushForTesting(); }
+
   // Exposed for testing, should not generally be used.
   void EnableTestingMode() { internal_state_.EnableTestingMode(); }
 
  private:
   internal::BindingState<Interface, Interface::PassesAssociatedKinds_>
       internal_state_;
 
   DISALLOW_COPY_AND_ASSIGN(Binding);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_BINDING_H_