Mojo C++ bindings: Simplify associated interface API.

mojo/public/cpp/bindings/interface_endpoint_client.h

Index: mojo/public/cpp/bindings/interface_endpoint_client.h
diff --git a/mojo/public/cpp/bindings/interface_endpoint_client.h b/mojo/public/cpp/bindings/interface_endpoint_client.h
index 5c5243ca2145f76bcc21b0e268d3a483ab44d981..0aea75678adc196caf49dec10f57e33bba48b3c2 100644
--- a/mojo/public/cpp/bindings/interface_endpoint_client.h
+++ b/mojo/public/cpp/bindings/interface_endpoint_client.h
@@ -31,7 +31,6 @@
 namespace mojo {
 
 class AssociatedGroup;
-class AssociatedGroupController;
 class InterfaceEndpointController;
 
 // InterfaceEndpointClient handles message sending and receiving of an interface
@@ -77,11 +76,7 @@ class MOJO_CPP_BINDINGS_EXPORT InterfaceEndpointClient
     return !async_responders_.empty() || !sync_responses_.empty();
   }
 
-  AssociatedGroupController* group_controller() const {
-    return handle_.group_controller();
-  }
   AssociatedGroup* associated_group();
-  uint32_t interface_id() const;
 
   // Adds a MessageReceiver which can filter a message after validation but
   // before dispatch.
@@ -97,6 +92,8 @@ class MOJO_CPP_BINDINGS_EXPORT InterfaceEndpointClient
   void CloseWithReason(uint32_t custom_reason, const std::string& description);
 
   // MessageReceiverWithResponder implementation:
+  // They must only be called when the handle is not in pending association
+  // state.
   bool Accept(Message* message) override;
   bool AcceptWithResponder(Message* message,
                            MessageReceiver* responder) override;
@@ -108,9 +105,12 @@ class MOJO_CPP_BINDINGS_EXPORT InterfaceEndpointClient
   bool HandleIncomingMessage(Message* message);
   void NotifyError(const base::Optional<DisconnectReason>& reason);
 
-  internal::ControlMessageProxy* control_message_proxy() {
-    return &control_message_proxy_;
-  }
+  // The following methods send interface control messages.
+  // They must only be called when the handle is not in pending association
+  // state.
+  void QueryVersion(const base::Callback<void(uint32_t)>& callback);
+  void RequireVersion(uint32_t version);
+  void FlushForTesting();
 
  private:
   // Maps from the id of a response to the MessageReceiver that handles the
@@ -150,24 +150,31 @@ class MOJO_CPP_BINDINGS_EXPORT InterfaceEndpointClient
     DISALLOW_COPY_AND_ASSIGN(HandleIncomingMessageThunk);
   };
 
+  void InitControllerIfNecessary();
+
+  void OnAssociationEvent(
+      ScopedInterfaceEndpointHandle::AssociationEvent event);
+
   bool HandleValidatedMessage(Message* message);
 
+  const bool expect_sync_requests_ = false;
+
   ScopedInterfaceEndpointHandle handle_;
   std::unique_ptr<AssociatedGroup> associated_group_;
-  InterfaceEndpointController* controller_;
+  InterfaceEndpointController* controller_ = nullptr;
 
-  MessageReceiverWithResponderStatus* const incoming_receiver_;
+  MessageReceiverWithResponderStatus* const incoming_receiver_ = nullptr;
   HandleIncomingMessageThunk thunk_;
   FilterChain filters_;
 
   AsyncResponderMap async_responders_;
   SyncResponseMap sync_responses_;
 
-  uint64_t next_request_id_;
+  uint64_t next_request_id_ = 1;
 
   base::Closure error_handler_;
   ConnectionErrorWithReasonCallback error_with_reason_handler_;
-  bool encountered_error_;
+  bool encountered_error_ = false;
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;