Add a receiver interface to RemovableStorageNotifications.

chrome/browser/system_monitor/removable_device_notifications_window_win_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 <windows.h>
 #include <dbt.h>
 
 #include <string>
 #include <vector>
 
@@ skipping 82 matching lines @@
   window_->Init();
   RunUntilIdle();
   window_->AddObserver(&observer_);
 }
 
 void RemovableDeviceNotificationsWindowWinTest::TearDown() {
   RunUntilIdle();
   window_->RemoveObserver(&observer_);
 }
 
-
 void RemovableDeviceNotificationsWindowWinTest::PreAttachDevices() {
   window_.reset();
   volume_mount_watcher_ = new TestVolumeMountWatcherWin;
   volume_mount_watcher_->SetAttachedDevicesFake();
 
   int expect_attach_calls = 0;
   std::vector<base::FilePath> initial_devices =
       volume_mount_watcher_->GetAttachedDevices();
   for (std::vector<base::FilePath>::const_iterator it = initial_devices.begin();
        it != initial_devices.end(); ++it) {
@@ skipping 396 matching lines @@
               pnp_device_id);
     EXPECT_EQ(it->object_persistent_id,
               TestPortableDeviceWatcherWin::GetMTPStorageUniqueId(
                   pnp_device_id, storage_object_id));
   }
   DoMTPDeviceTest(TestPortableDeviceWatcherWin::kMTPDeviceWithValidInfo, false);
 }
 
 }  // namespace test
 }  // namespace chrome