Remove IPC::Endpoint.

ipc/ipc_channel_mojo.h

Index: ipc/ipc_channel_mojo.h
diff --git a/ipc/ipc_channel_mojo.h b/ipc/ipc_channel_mojo.h
index ddc00c0d537400fea3df2a13909d7258e2fc01c9..215b198d60c25ddc85996837e8b4c356ea74d863 100644
--- a/ipc/ipc_channel_mojo.h
+++ b/ipc/ipc_channel_mojo.h
@@ -73,11 +73,8 @@ class IPC_EXPORT ChannelMojo
   void Flush() override;
   void Close() override;
   bool Send(Message* message) override;
-  base::ProcessId GetPeerPID() const override;
   Channel::AssociatedInterfaceSupport* GetAssociatedInterfaceSupport() override;
 
-  base::ProcessId GetSelfPID() const;
-
   // These access protected API of IPC::Message, which has ChannelMojo
   // as a friend class.
   static MojoResult WriteToMessageAttachmentSet(
@@ -92,7 +89,7 @@ class IPC_EXPORT ChannelMojo
                         mojom::ChannelAssociatedRequest receiver) override;
 
   // MessagePipeReader::Delegate
-  void OnPeerPidReceived() override;
+  void OnPeerPidReceived(int32_t peer_pid) override;
   void OnMessageReceived(const Message& message) override;
   void OnPipeError() override;
   void OnAssociatedInterfaceRequest(