ipc: Move methods into AttachmentBroker interface.

ipc/attachment_broker_privileged_mac.h

Index: ipc/attachment_broker_privileged_mac.h
diff --git a/ipc/attachment_broker_privileged_mac.h b/ipc/attachment_broker_privileged_mac.h
index f8a2871b4b2d16cdc681f82a48a7b009107dbc3a..c6776f64e1c07fa70a740792ac8a77a685faa33d 100644
--- a/ipc/attachment_broker_privileged_mac.h
+++ b/ipc/attachment_broker_privileged_mac.h
@@ -50,10 +50,6 @@ class IPC_EXPORT AttachmentBrokerPrivilegedMac
   AttachmentBrokerPrivilegedMac();
   ~AttachmentBrokerPrivilegedMac() override;
 
-  // The port provider must live as long as the AttachmentBrokerPrivilegedMac. A
-  // port provider must be set before any attachment brokering occurs.
-  void SetPortProvider(base::PortProvider* port_provider);
-
   // IPC::AttachmentBroker overrides.
   bool SendAttachmentToProcess(BrokerableAttachment* attachment,
                                base::ProcessId destination_process) override;
@@ -122,8 +118,6 @@ class IPC_EXPORT AttachmentBrokerPrivilegedMac
   // that receives the Chrome IPC message.
   void RouteWireFormatToAnother(const MachPortWireFormat& wire_format);
 
-  base::PortProvider* port_provider_;
-
   DISALLOW_COPY_AND_ASSIGN(AttachmentBrokerPrivilegedMac);
 };