Mojo C++ bindings: make InterfaceEndpointClient observe message loop destruction.

mojo/public/cpp/bindings/interface_endpoint_client.h

 // Copyright 2015 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_INTERFACE_ENDPOINT_CLIENT_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_ENDPOINT_CLIENT_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <memory>
 
 #include "base/callback.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
+#include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_checker.h"
 #include "mojo/public/cpp/bindings/connection_error_callback.h"
 #include "mojo/public/cpp/bindings/filter_chain.h"
 #include "mojo/public/cpp/bindings/lib/control_message_handler.h"
 #include "mojo/public/cpp/bindings/lib/control_message_proxy.h"
 #include "mojo/public/cpp/bindings/message.h"
 #include "mojo/public/cpp/bindings/scoped_interface_endpoint_handle.h"
 
 namespace mojo {
 
 class AssociatedGroup;
 class AssociatedGroupController;
 class InterfaceEndpointController;
 
 // InterfaceEndpointClient handles message sending and receiving of an interface
 // endpoint, either the implementation side or the client side.
 // It should only be accessed and destructed on the creating thread.
-class InterfaceEndpointClient : public MessageReceiverWithResponder {
+class InterfaceEndpointClient : public MessageReceiverWithResponder,
+                                public base::MessageLoop::DestructionObserver {
  public:
   // |receiver| is okay to be null. If it is not null, it must outlive this
   // object.
   InterfaceEndpointClient(ScopedInterfaceEndpointHandle handle,
                           MessageReceiverWithResponderStatus* receiver,
                           std::unique_ptr<MessageReceiver> payload_validator,
                           bool expect_sync_requests,
                           scoped_refptr<base::SingleThreadTaskRunner> runner,
                           uint32_t interface_version);
   ~InterfaceEndpointClient() override;
@@ skipping 90 matching lines @@
     // MessageReceiver implementation:
     bool Accept(Message* message) override;
 
    private:
     InterfaceEndpointClient* const owner_;
 
     DISALLOW_COPY_AND_ASSIGN(HandleIncomingMessageThunk);
   };
 
   bool HandleValidatedMessage(Message* message);
+  void StopObservingIfNecessary();
+
+  // base::MessageLoop::DestructionObserver:
+  void WillDestroyCurrentMessageLoop() override;
 
   ScopedInterfaceEndpointHandle handle_;
   std::unique_ptr<AssociatedGroup> associated_group_;
   InterfaceEndpointController* controller_;
 
   MessageReceiverWithResponderStatus* const incoming_receiver_;
   HandleIncomingMessageThunk thunk_;
   FilterChain filters_;
 
   AsyncResponderMap async_responders_;
   SyncResponseMap sync_responses_;
 
   uint64_t next_request_id_;
 
   base::Closure error_handler_;
   ConnectionErrorWithReasonCallback error_with_reason_handler_;
   bool encountered_error_;
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   internal::ControlMessageProxy control_message_proxy_;
   internal::ControlMessageHandler control_message_handler_;
 
+  bool observing_message_loop_destruction_ = true;
+
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<InterfaceEndpointClient> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(InterfaceEndpointClient);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_ENDPOINT_CLIENT_H_