Rename various Proxy classes. Provide a Proxy interface.

corelib/src/implementation/promise_implementation.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Dart core library.
 
 class PromiseImpl<T> implements Promise<T> {
 
   // Enumeration of possible states:
   static final int CREATED = 0;
@@ skipping 244 matching lines @@
     addCompleteHandler((val) {
       promises.forEach((promise) {
         if (!promise.isDone()) {
           promise.cancel();
         }
       });
     });
   }
 }
 
-class ProxyImpl {
+class ProxyBase {
 
-  ProxyImpl.forPort(SendPort port) {
+  ProxyBase.forPort(SendPort port) {
     _promise = new Promise<SendPort>();
     _promise.complete(port);
   }
 
   // Construct a proxy for a message reply; see the [Proxy.forReply]
   // documentation for more details.
-  ProxyImpl.forReply(Promise<SendPort> port) {
+  ProxyBase.forReply(Promise<SendPort> port) {
     _promise = port;
   }
 
   // Note that comparing proxies or using them in maps is illegal
   // until they complete.
   bool operator ==(var other) {
-    return (other is ProxyImpl) && _promise.value == other._promise.value;
+    return (other is ProxyBase) && _promise.value == other._promise.value;
   }
 
   int hashCode() => _promise.value.hashCode();
 
   // TODO: consider making this extend Promise<SendPort> instead?
   void addCompleteHandler(void completeHandler()) {
     _promise.addCompleteHandler((_) => completeHandler());
   }
 
   static ReceivePort register(Dispatcher dispatcher) {
@@ skipping 78 matching lines @@
         } 
       }
       return process(marshalled);
     }).flatten();
   }
 
   Promise<SendPort> _promise;
   static Map<SendPort, Dispatcher> _dispatchers;
 
 }