Add support for attaching filters to an IPC TestSink.

ipc/ipc_test_sink.cc

 // Copyright (c) 2011 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.
 
 #include "ipc/ipc_test_sink.h"
 
 #include "ipc/ipc_message.h"
 
 namespace IPC {
 
 TestSink::TestSink() {
 }
 
 TestSink::~TestSink() {
 }
 
 bool TestSink::Send(Message* message) {
   OnMessageReceived(*message);
   delete message;
   return true;
 }
 
 bool TestSink::OnMessageReceived(const Message& msg) {
+  ObserverListBase<Channel::Listener>::Iterator it(filter_list_);
+  Channel::Listener* observer;
+  while ((observer = it.GetNext()) != NULL) {
+    if (observer->OnMessageReceived(msg))
+      return true;
+  }
+
+  // No filter handled the message, so store it.
   messages_.push_back(Message(msg));
   return true;
 }
 
 void TestSink::ClearMessages() {
   messages_.clear();
 }
 
 const Message* TestSink::GetMessageAt(size_t index) const {
   if (index >= messages_.size())
@@ skipping 16 matching lines @@
     if (messages_[i].type() == id) {
       found_count++;
       found_index = i;
     }
   }
   if (found_count != 1)
     return NULL;  // Didn't find a unique one.
   return &messages_[found_index];
 }
 
+void TestSink::AddFilter(Channel::Listener* filter) {
+  filter_list_.AddObserver(filter);
+}
+
+void TestSink::RemoveFilter(Channel::Listener* filter) {
+  filter_list_.RemoveObserver(filter);
+}
+
 }  // namespace IPC