InterfacePtr: not configure proxy until actual read/write is needed.

mojo/public/cpp/bindings/interface_ptr.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_INTERFACE_PTR_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_PTR_H_
 
 #include <assert.h>
 
 #include <algorithm>
@@ skipping 42 matching lines @@
   bool WaitForIncomingMethodCall() {
     return internal_state_.WaitForIncomingMethodCall();
   }
 
   // This method configures the InterfacePtr<..> to be a proxy to a remote
   // object on the other end of the given pipe.
   //
   // The proxy is bound to the current thread, which means its methods may
   // only be called on the current thread.
   //
-  // To move a bound InterfacePtr<..> to another thread, call
-  // ResetAndReturnMessagePipe. Then create a new InterfacePtr<..> on another
-  // thread, and bind the new InterfacePtr<..> to the message pipe on that
-  // thread.
+  // To move a bound InterfacePtr<..> to another thread, call PassMessagePipe().
+  // Then create a new InterfacePtr<..> on another thread, and bind the new
+  // InterfacePtr<..> to the message pipe on that thread.
   void Bind(
       ScopedMessagePipeHandle handle,
       const MojoAsyncWaiter* waiter = Environment::GetDefaultAsyncWaiter()) {
     reset();
-    internal_state_.ConfigureProxy(handle.Pass(), waiter);
+    internal_state_.Bind(handle.Pass(), waiter);
   }
 
   // The client interface may only be set after this InterfacePtr<..> is bound.
   void set_client(typename Interface::Client* client) {
     internal_state_.set_client(client);
   }
 
   // This method may be called to query if the underlying pipe has encountered
   // an error. If true, this means method calls made on this interface will be
   // dropped (and may have already been dropped) on the floor.
   bool encountered_error() const {
-    assert(internal_state_.router());
-    return internal_state_.router()->encountered_error();
+    return internal_state_.encountered_error();
   }
 
   // This method may be called to register an ErrorHandler to observe a
-  // connection error on the underlying pipe. The callback runs asynchronously
-  // from the current message loop.
+  // connection error on the underlying pipe. It must only be called on a bound
+  // object.
+  // The callback runs asynchronously from the current message loop.
   void set_error_handler(ErrorHandler* error_handler) {
-    assert(internal_state_.router());
-    internal_state_.router()->set_error_handler(error_handler);
+    internal_state_.set_error_handler(error_handler);
   }
 
   // Returns the underlying message pipe handle (if any) and resets the
   // InterfacePtr<..> to its uninitialized state. This method is helpful if you
   // need to move a proxy to another thread. See related notes for Bind.
   ScopedMessagePipeHandle PassMessagePipe() {
     State state;
     internal_state_.Swap(&state);
-    return state.router() ?
-        state.router()->PassMessagePipe() : ScopedMessagePipeHandle();
+    return state.PassMessagePipe();
   }
 
   // DO NOT USE. Exposed only for internal use and for testing.
   internal::InterfacePtrState<Interface>* internal_state() {
     return &internal_state_;
   }
 
  private:
   typedef internal::InterfacePtrState<Interface> State;
-  State internal_state_;
+  mutable State internal_state_;
 };
 
 // Takes a handle to the proxy end-point of a pipe. On the other end is
 // presumed to be an interface implementation of type |Interface|. Returns a
 // generated proxy to that interface, which may be used on the current thread.
 // It is valid to call set_client on the returned InterfacePtr<..> to set an
 // instance of Interface::Client.
 template <typename Interface>
 InterfacePtr<Interface> MakeProxy(
     ScopedMessagePipeHandle handle,
     const MojoAsyncWaiter* waiter = Environment::GetDefaultAsyncWaiter()) {
   InterfacePtr<Interface> ptr;
   if (handle.is_valid())
     ptr.Bind(handle.Pass(), waiter);
   return ptr.Pass();
 }
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_PTR_H_