[Media Galleries] Lazily initialize the storage monitor.

chrome/browser/storage_monitor/storage_monitor_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/message_loop.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/storage_monitor/mock_removable_storage_observer.h"
 #include "chrome/browser/storage_monitor/storage_monitor.h"
 #include "chrome/browser/storage_monitor/test_storage_monitor.h"
+#include "content/public/test/test_browser_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace chrome {
 
 TEST(StorageMonitorTest, TestInitialize) {
+  MessageLoopForUI message_loop_;
+  content::TestBrowserThread(content::BrowserThread::UI, &message_loop_);
   test::TestStorageMonitor monitor;
   EXPECT_FALSE(monitor.init_called_);
 
   base::WaitableEvent event(false, false);
   monitor.Initialize(base::Bind(&base::WaitableEvent::Signal,
                                 base::Unretained(&event)));
   EXPECT_TRUE(monitor.init_called_);
   EXPECT_FALSE(event.IsSignaled());
   monitor.MarkInitialized();
   EXPECT_TRUE(event.IsSignaled());
@@ skipping 93 matching lines @@
   EXPECT_EQ(kDeviceName2, devices[0].name);
   EXPECT_EQ(kDevicePath2.value(), devices[0].location);
 
   monitor.receiver()->ProcessDetach(kDeviceId2);
   message_loop.RunUntilIdle();
   devices = monitor.GetAttachedStorage();
   EXPECT_EQ(0U, devices.size());
 }
 
 }  // namespace chrome