ResizingHostObserver is created by the desktop environment together with other stubs.

remoting/host/chromoting_host_unittest.cc

 // Copyright (c) 2012 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 "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop_proxy.h"
 #include "media/video/capture/screen/screen_capturer_fake.h"
 #include "remoting/base/auto_thread_task_runner.h"
@@ skipping 276 matching lines @@
 
   // Creates a DesktopEnvironment with a fake media::ScreenCapturer, to mock
   // DesktopEnvironmentFactory::Create().
   DesktopEnvironment* CreateDesktopEnvironment() {
     MockDesktopEnvironment* desktop_environment = new MockDesktopEnvironment();
     EXPECT_CALL(*desktop_environment, CreateAudioCapturerPtr(_))
         .Times(0);
     EXPECT_CALL(*desktop_environment, CreateEventExecutorPtr(_, _))
         .Times(AnyNumber())
         .WillRepeatedly(Invoke(this, &ChromotingHostTest::CreateEventExecutor));
+    EXPECT_CALL(*desktop_environment, CreateSessionControllerPtr())
+        .Times(AnyNumber())
+        .WillRepeatedly(Invoke(this,
+                               &ChromotingHostTest::CreateSessionController));
     EXPECT_CALL(*desktop_environment, CreateVideoCapturerPtr(_, _))
         .Times(AnyNumber())
         .WillRepeatedly(Invoke(this, &ChromotingHostTest::CreateVideoCapturer));
 
     return desktop_environment;
   }
 
   // Creates a dummy EventExecutor, to mock
   // DesktopEnvironment::CreateEventExecutor().
   EventExecutor* CreateEventExecutor(
       scoped_refptr<base::SingleThreadTaskRunner> input_task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner) {
     MockEventExecutor* event_executor = new MockEventExecutor();
     EXPECT_CALL(*event_executor, StartPtr(_));
     return event_executor;
   }
 
+  // Creates a dummy SessionController, to mock
+  // DesktopEnvironment::CreateSessionController().
+  SessionController* CreateSessionController() {
+    return new MockSessionController();
+  }
+
   // Creates a fake media::ScreenCapturer, to mock
   // DesktopEnvironment::CreateVideoCapturer().
   media::ScreenCapturer* CreateVideoCapturer(
       scoped_refptr<base::SingleThreadTaskRunner> capture_task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> encode_task_runner) {
     return new media::ScreenCapturerFake();
   }
 
   void DisconnectAllClients() {
     host_->DisconnectAllClients();
@@ skipping 395 matching lines @@
   ExpectClientDisconnected(0, true, video_packet_sent,
       InvokeWithoutArgs(this, &ChromotingHostTest::ShutdownHost));
   EXPECT_CALL(host_status_observer_, OnShutdown());
 
   host_->Start(xmpp_login_);
   SimulateClientConnection(0, true, false);
   message_loop_.Run();
 }
 
 }  // namespace remoting