Chrome changes corresponding to my message_loop_type CL.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@1363 0039d316-1c4b-4281-b951-d872f2087c98

103 files changed, 341 insertions, 236 deletions

diff --git a/chrome/app/chrome_dll_main.cc b/chrome/app/chrome_dll_main.cc
index dd2a08b..01d68c0 100644
--- a/chrome/app/chrome_dll_main.cc
+++ b/chrome/app/chrome_dll_main.cc
@@ -200,9 +200,6 @@ DLLEXPORT int __cdecl ChromeMain(HINSTANCE instance,
 
   _Module.Init(NULL, instance);
 
-  // Allocate a message loop for this thread
-  MessageLoop main_message_loop;
-
   // Notice a user data directory override if any
   const std::wstring user_data_dir =
       parsed_command_line.GetSwitchValue(switches::kUserDataDir);
diff --git a/chrome/browser/autocomplete/autocomplete_unittest.cc b/chrome/browser/autocomplete/autocomplete_unittest.cc
index 22f6399..cadda8d 100644
--- a/chrome/browser/autocomplete/autocomplete_unittest.cc
+++ b/chrome/browser/autocomplete/autocomplete_unittest.cc
@@ -110,6 +110,7 @@ class AutocompleteProviderTest : public testing::Test,
   AutocompleteResult result_;
 
  private:
+  MessageLoopForUI message_loop_;
   scoped_ptr<AutocompleteController> controller_;
 };
 
diff --git a/chrome/browser/autocomplete/history_contents_provider_unittest.cc b/chrome/browser/autocomplete/history_contents_provider_unittest.cc
index 5ef13b6..ba7985a 100644
--- a/chrome/browser/autocomplete/history_contents_provider_unittest.cc
+++ b/chrome/browser/autocomplete/history_contents_provider_unittest.cc
@@ -97,6 +97,8 @@ class HistoryContentsProviderTest : public testing::Test,
     MessageLoop::current()->Quit();
   }
 
+  MessageLoopForUI message_loop_;
+  
   std::wstring history_dir_;
 
   scoped_refptr<HistoryContentsProvider> provider_;
diff --git a/chrome/browser/autocomplete/history_url_provider_unittest.cc b/chrome/browser/autocomplete/history_url_provider_unittest.cc
index 9ef0172..05a696d 100644
--- a/chrome/browser/autocomplete/history_url_provider_unittest.cc
+++ b/chrome/browser/autocomplete/history_url_provider_unittest.cc
@@ -98,6 +98,7 @@ class HistoryURLProviderTest : public testing::Test,
                const std::wstring* expected_urls,
                int num_results);
 
+  MessageLoopForUI message_loop_;
   ACMatches matches_;
   scoped_ptr<TestingProfile> profile_;
   HistoryService* history_service_;
diff --git a/chrome/browser/back_forward_menu_model_unittest.cc b/chrome/browser/back_forward_menu_model_unittest.cc
index 2b57e21..d13e12d 100644
--- a/chrome/browser/back_forward_menu_model_unittest.cc
+++ b/chrome/browser/back_forward_menu_model_unittest.cc
@@ -121,6 +121,7 @@ class BackFwdMenuModelTest : public testing::Test {
   }
 
  private:
+  MessageLoopForUI message_loop_;
   std::wstring test_dir_;
   std::wstring profile_path_;
   ProfileManager pm_;
diff --git a/chrome/browser/bookmark_bar_context_menu_controller_test.cc b/chrome/browser/bookmark_bar_context_menu_controller_test.cc
index 5914e87..4c2cfa4 100644
--- a/chrome/browser/bookmark_bar_context_menu_controller_test.cc
+++ b/chrome/browser/bookmark_bar_context_menu_controller_test.cc
@@ -30,7 +30,8 @@ class TestingPageNavigator : public PageNavigator {
 
 class BookmarkBarContextMenuControllerTest : public testing::Test {
  public:
-  BookmarkBarContextMenuControllerTest() : bb_view_(NULL), model_(NULL) {
+  BookmarkBarContextMenuControllerTest()
+      : bb_view_(NULL), model_(NULL) {
   }
 
   virtual void SetUp() {
@@ -53,6 +54,7 @@ class BookmarkBarContextMenuControllerTest : public testing::Test {
   }
 
  protected:
+  MessageLoopForUI message_loop_;
   scoped_ptr<TestingProfile> profile_;
   BookmarkBarModel* model_;
   scoped_ptr<BookmarkBarView> bb_view_;
diff --git a/chrome/browser/bookmark_bar_model_unittest.cc b/chrome/browser/bookmark_bar_model_unittest.cc
index 4e2a78a..809084e 100644
--- a/chrome/browser/bookmark_bar_model_unittest.cc
+++ b/chrome/browser/bookmark_bar_model_unittest.cc
@@ -525,6 +525,8 @@ class BookmarkBarModelTestWithProfile : public testing::Test,
                                    BookmarkBarNode* node) {}
   virtual void BookmarkNodeFavIconLoaded(BookmarkBarModel* model,
                                          BookmarkBarNode* node) {}
+
+  MessageLoopForUI message_loop_;
 };
 
 // Creates a set of nodes in the bookmark bar model, then recreates the
diff --git a/chrome/browser/bookmark_storage.h b/chrome/browser/bookmark_storage.h
index 969fa0a..137ccb4 100644
--- a/chrome/browser/bookmark_storage.h
+++ b/chrome/browser/bookmark_storage.h
@@ -49,7 +49,7 @@ class BookmarkStorage : public base::RefCountedThreadSafe<BookmarkStorage> {
   void SaveNow();

 

   // Returns the thread the backend is run on.

-  Thread* backend_thread() const { return backend_thread_; }

+  base::Thread* backend_thread() const { return backend_thread_; }

 

   // The model. The model is NULL once BookmarkModelDeleted has been invoked.

   BookmarkBarModel* model_;

@@ -62,7 +62,7 @@ class BookmarkStorage : public base::RefCountedThreadSafe<BookmarkStorage> {
 

   // Thread read/writing is run on. This comes from the profile, and is null

   // during testing.

-  Thread* backend_thread_;

+  base::Thread* backend_thread_;

 

   DISALLOW_COPY_AND_ASSIGN(BookmarkStorage);

 };

diff --git a/chrome/browser/browser_main.cc b/chrome/browser/browser_main.cc
index b3357f0..8555784 100644
--- a/chrome/browser/browser_main.cc
+++ b/chrome/browser/browser_main.cc
@@ -245,9 +245,11 @@ int BrowserMain(CommandLine &parsed_command_line, int show_command,
   // TODO(beng, brettw): someday, break this out into sub functions with well
   //                     defined roles (e.g. pre/post-profile startup, etc).
 
+  MessageLoop main_message_loop(MessageLoop::TYPE_UI);
+
   const char* main_thread_name = "Chrome_BrowserMain";
   PlatformThread::SetName(main_thread_name);
-  MessageLoop::current()->set_thread_name(main_thread_name);
+  main_message_loop.set_thread_name(main_thread_name);
   bool already_running = CreateUniqueChromeEvent();
 
   // Make the selection of network stacks early on before any consumers try to
@@ -480,7 +482,7 @@ int BrowserMain(CommandLine &parsed_command_line, int show_command,
   if (BrowserInit::ProcessCommandLine(parsed_command_line, L"", local_state,
                                       show_command, true, profile,
                                       &result_code)) {
-    MessageLoop::current()->Run(browser_process->accelerator_handler());
+    MessageLoopForUI::current()->Run(browser_process->accelerator_handler());
   }
 
   if (metrics)
diff --git a/chrome/browser/browser_process.h b/chrome/browser/browser_process.h
index fb3348d..908af1a 100644
--- a/chrome/browser/browser_process.h
+++ b/chrome/browser/browser_process.h
@@ -26,11 +26,13 @@ class ProfileManager;
 class RenderProcessHost;
 class ResourceDispatcherHost;
 class DebuggerWrapper;
-class Thread;
 class WebAppInstallerService;
 class SharedEvent;
 class SuspendController;
 
+namespace base {
+class Thread;
+}
 namespace sandbox {
 class BrokerServices;
 }
@@ -81,16 +83,16 @@ class BrowserProcess {
   // Returns the thread that we perform I/O coordination on (network requests,
   // communication with renderers, etc.
   // NOTE: need to check the return value for NULL.
-  virtual Thread* io_thread() = 0;
+  virtual base::Thread* io_thread() = 0;
 
   // Returns the thread that we perform random file operations on. For code
   // that wants to do I/O operations (not network requests or even file: URL
   // requests), this is the thread to use to avoid blocking the UI thread.
   // It might be nicer to have a thread pool for this kind of thing.
-  virtual Thread* file_thread() = 0;
+  virtual base::Thread* file_thread() = 0;
 
   // Returns the thread that is used for database operations such as history.
-  virtual Thread* db_thread() = 0;
+  virtual base::Thread* db_thread() = 0;
 
   virtual sandbox::BrokerServices* broker_services() = 0;
 
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index 57c0d71..5c218ca 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -269,8 +269,11 @@ void BrowserProcessImpl::CreateIOThread() {
   // invoke the io_thread() accessor.
   PluginService::GetInstance();
 
-  scoped_ptr<Thread> thread(new BrowserProcessSubThread(ChromeThread::IO));
-  if (!thread->Start())
+  scoped_ptr<base::Thread> thread(
+      new BrowserProcessSubThread(ChromeThread::IO));
+  base::Thread::Options options;
+  options.message_loop_type = MessageLoop::TYPE_IO;
+  if (!thread->StartWithOptions(options))
     return;
   io_thread_.swap(thread);
 }
@@ -279,7 +282,8 @@ void BrowserProcessImpl::CreateFileThread() {
   DCHECK(!created_file_thread_ && file_thread_.get() == NULL);
   created_file_thread_ = true;
 
-  scoped_ptr<Thread> thread(new BrowserProcessSubThread(ChromeThread::FILE));
+  scoped_ptr<base::Thread> thread(
+      new BrowserProcessSubThread(ChromeThread::FILE));
   if (!thread->Start())
     return;
   file_thread_.swap(thread);
@@ -289,7 +293,8 @@ void BrowserProcessImpl::CreateDBThread() {
   DCHECK(!created_db_thread_ && db_thread_.get() == NULL);
   created_db_thread_ = true;
 
-  scoped_ptr<Thread> thread(new BrowserProcessSubThread(ChromeThread::DB));
+  scoped_ptr<base::Thread> thread(
+      new BrowserProcessSubThread(ChromeThread::DB));
   if (!thread->Start())
     return;
   db_thread_.swap(thread);
diff --git a/chrome/browser/browser_process_impl.h b/chrome/browser/browser_process_impl.h
index 78bbbaa..82f275f 100644
--- a/chrome/browser/browser_process_impl.h
+++ b/chrome/browser/browser_process_impl.h
@@ -48,21 +48,21 @@ class BrowserProcessImpl : public BrowserProcess, public NonThreadSafe {
     return metrics_service_.get();
   }
 
-  virtual Thread* io_thread() {
+  virtual base::Thread* io_thread() {
     DCHECK(CalledOnValidThread());
     if (!created_io_thread_)
       CreateIOThread();
     return io_thread_.get();
   }
 
-  virtual Thread* file_thread() {
+  virtual base::Thread* file_thread() {
     DCHECK(CalledOnValidThread());
     if (!created_file_thread_)
       CreateFileThread();
     return file_thread_.get();
   }
 
-  virtual Thread* db_thread() {
+  virtual base::Thread* db_thread() {
     DCHECK(CalledOnValidThread());
     if (!created_db_thread_)
       CreateDBThread();
@@ -212,13 +212,13 @@ class BrowserProcessImpl : public BrowserProcess, public NonThreadSafe {
   scoped_ptr<MetricsService> metrics_service_;
 
   bool created_io_thread_;
-  scoped_ptr<Thread> io_thread_;
+  scoped_ptr<base::Thread> io_thread_;
 
   bool created_file_thread_;
-  scoped_ptr<Thread> file_thread_;
+  scoped_ptr<base::Thread> file_thread_;
 
   bool created_db_thread_;
-  scoped_ptr<Thread> db_thread_;
+  scoped_ptr<base::Thread> db_thread_;
 
   bool created_profile_manager_;
   scoped_ptr<ProfileManager> profile_manager_;
diff --git a/chrome/browser/browsing_data_remover.cc b/chrome/browser/browsing_data_remover.cc
index 78bb3b2..25891c9 100644
--- a/chrome/browser/browsing_data_remover.cc
+++ b/chrome/browser/browsing_data_remover.cc
@@ -107,7 +107,7 @@ void BrowsingDataRemover::Remove(int remove_mask) {
 
   if (remove_mask & REMOVE_CACHE) {
     // Invoke ClearBrowsingDataView::ClearCache on the IO thread.
-    Thread* thread = g_browser_process->io_thread();
+    base::Thread* thread = g_browser_process->io_thread();
     if (thread) {
       waiting_for_clear_cache_ = true;
       UserMetrics::RecordAction(L"ClearBrowsingData_Cache", profile_);
diff --git a/chrome/browser/cache_manager_host_unittest.cc b/chrome/browser/cache_manager_host_unittest.cc
index dda5108..e90d3c0 100644
--- a/chrome/browser/cache_manager_host_unittest.cc
+++ b/chrome/browser/cache_manager_host_unittest.cc
@@ -4,8 +4,8 @@
 
 #include <string>
 
+#include "base/message_loop.h"
 #include "chrome/browser/cache_manager_host.h"
-#include "base/basictypes.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "webkit/glue/cache_manager.h"
 
@@ -78,6 +78,9 @@ class CacheManagerHostTest : public testing::Test {
     KEEP_LIVE_WITH_HEADROOM = CacheManagerHost::KEEP_LIVE_WITH_HEADROOM,
     KEEP_LIVE = CacheManagerHost::KEEP_LIVE,
   };
+  
+ private:
+  MessageLoop message_loop_;
 };
 
 // static
diff --git a/chrome/browser/chrome_plugin_host.cc b/chrome/browser/chrome_plugin_host.cc
index 634cd5c..f9a54ea 100644
--- a/chrome/browser/chrome_plugin_host.cc
+++ b/chrome/browser/chrome_plugin_host.cc
@@ -73,9 +73,8 @@ class PluginRequestInterceptor
   }
 
   void RegisterProtocol(const std::string& scheme) {
-#ifndef NDEBUG
-    DCHECK(MessageLoop::current() == message_loop_);
-#endif
+    DCHECK(CalledOnValidThread());
+
     std::string lower_scheme = StringToLowerASCII(scheme);
     handled_protocols_.insert(lower_scheme);
 
@@ -90,9 +89,7 @@ class PluginRequestInterceptor
 
   // URLRequest::Interceptor
   virtual URLRequestJob* MaybeIntercept(URLRequest* request) {
-#ifndef NDEBUG
-    DCHECK(MessageLoop::current() == message_loop_);
-#endif
+    DCHECK(CalledOnValidThread());
 
     if (!IsHandledProtocol(request->url().scheme()))
       return NULL;
diff --git a/chrome/browser/chrome_thread.h b/chrome/browser/chrome_thread.h
index a8855ea..9a9cd45 100644
--- a/chrome/browser/chrome_thread.h
+++ b/chrome/browser/chrome_thread.h
@@ -26,7 +26,7 @@
 // handling pointers to threads because many of the well-known threads are owned
 // by the UI thread and can be deallocated without notice.
 //
-class ChromeThread : public Thread {
+class ChromeThread : public base::Thread {
  public:
   // An enumeration of the well-known threads.
   enum ID {
diff --git a/chrome/browser/download_file.cc b/chrome/browser/download_file.cc
index d025377..a7f796e 100644
--- a/chrome/browser/download_file.cc
+++ b/chrome/browser/download_file.cc
@@ -415,7 +415,7 @@ void DownloadFileManager::DownloadUrl(const GURL& url,
                                       int render_view_id,
                                       URLRequestContext* request_context) {
   DCHECK(MessageLoop::current() == ui_loop_);
-  Thread* thread = g_browser_process->io_thread();
+  base::Thread* thread = g_browser_process->io_thread();
   if (thread) {
     thread->message_loop()->PostTask(FROM_HERE,
         NewRunnableMethod(this,
diff --git a/chrome/browser/download_manager.cc b/chrome/browser/download_manager.cc
index 94a9db0..aef9b14 100644
--- a/chrome/browser/download_manager.cc
+++ b/chrome/browser/download_manager.cc
@@ -668,7 +668,7 @@ void DownloadManager::DownloadFinished(int32 download_id, int64 size) {
 void DownloadManager::CancelDownloadRequest(int render_process_id,
                                             int request_id) {
   ResourceDispatcherHost* rdh = g_browser_process->resource_dispatcher_host();
-  Thread* io_thread = g_browser_process->io_thread();
+  base::Thread* io_thread = g_browser_process->io_thread();
   if (!io_thread || !rdh)
     return;
   io_thread->message_loop()->PostTask(FROM_HERE,
@@ -717,7 +717,7 @@ void DownloadManager::PauseDownload(int32 download_id, bool pause) {
       return;
 
     // Inform the ResourceDispatcherHost of the new pause state.
-    Thread* io_thread = g_browser_process->io_thread();
+    base::Thread* io_thread = g_browser_process->io_thread();
     ResourceDispatcherHost* rdh = g_browser_process->resource_dispatcher_host();
     if (!io_thread || !rdh)
       return;
diff --git a/chrome/browser/download_manager.h b/chrome/browser/download_manager.h
index b05b26d..89773fe 100644
--- a/chrome/browser/download_manager.h
+++ b/chrome/browser/download_manager.h
@@ -60,11 +60,13 @@ class PrefService;
 class Profile;
 class ResourceDispatcherHost;
 class Task;
-class Thread;
 class Timer;
 class URLRequestContext;
 class WebContents;
 
+namespace base {
+class Thread;
+}
 
 // DownloadItem ----------------------------------------------------------------
 
diff --git a/chrome/browser/first_run.cc b/chrome/browser/first_run.cc
index d06d365..097ec77 100644
--- a/chrome/browser/first_run.cc
+++ b/chrome/browser/first_run.cc
@@ -164,7 +164,7 @@ void OpenFirstRunDialog(Profile* profile) {
   // is closed) so that the window can receive messages and we block the
   // browser window from showing up. We pass the accelerator handler here so
   // that keyboard accelerators (Enter, Esc, etc) work in the dialog box.
-  MessageLoop::current()->Run(g_browser_process->accelerator_handler());
+  MessageLoopForUI::current()->Run(g_browser_process->accelerator_handler());
 }
 
 namespace {
diff --git a/chrome/browser/history/expire_history_backend_unittest.cc b/chrome/browser/history/expire_history_backend_unittest.cc
index 1a892d6..fba70eb 100644
--- a/chrome/browser/history/expire_history_backend_unittest.cc
+++ b/chrome/browser/history/expire_history_backend_unittest.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "base/basictypes.h"
+#include "base/compiler_specific.h"
 #include "base/file_util.h"
 #include "base/path_service.h"
 #include "base/scoped_ptr.h"
@@ -27,8 +28,8 @@ namespace history {
 class ExpireHistoryTest : public testing::Test,
                           public BroadcastNotificationDelegate {
  public:
-#pragma warning(suppress: 4355)  // OK to pass "this" here.
-  ExpireHistoryTest() : expirer_(this), now_(Time::Now()) {
+  ExpireHistoryTest()
+      : ALLOW_THIS_IN_INITIALIZER_LIST(expirer_(this)), now_(Time::Now()) {
   }
 
  protected:
@@ -56,6 +57,8 @@ class ExpireHistoryTest : public testing::Test,
 
   static bool IsStringInFile(std::wstring& filename, const char* str);
 
+  MessageLoop message_loop_;
+
   ExpireHistoryBackend expirer_;
 
   scoped_ptr<HistoryDatabase> main_db_;
diff --git a/chrome/browser/history/history_backend_unittest.cc b/chrome/browser/history/history_backend_unittest.cc
index b664f9b..baf5f0e 100644
--- a/chrome/browser/history/history_backend_unittest.cc
+++ b/chrome/browser/history/history_backend_unittest.cc
@@ -98,6 +98,7 @@ class HistoryBackendTest : public testing::Test {
     delete details;
   }
 
+  MessageLoop message_loop_;
   std::wstring test_dir_;
 };
 
diff --git a/chrome/browser/history/history_querying_unittest.cc b/chrome/browser/history/history_querying_unittest.cc
index 6189044..c62fc40 100644
--- a/chrome/browser/history/history_querying_unittest.cc
+++ b/chrome/browser/history/history_querying_unittest.cc
@@ -124,6 +124,8 @@ class HistoryQueryTest : public testing::Test {
     MessageLoop::current()->Quit();  // Will return out to QueryHistory.
   }
 
+  MessageLoop message_loop_;
+  
   std::wstring history_dir_;
 
   CancelableRequestConsumer consumer_;
diff --git a/chrome/browser/history/history_unittest.cc b/chrome/browser/history/history_unittest.cc
index e589f11..29f674e 100644
--- a/chrome/browser/history/history_unittest.cc
+++ b/chrome/browser/history/history_unittest.cc
@@ -240,6 +240,8 @@ class HistoryTest : public testing::Test {
       saved_redirects_.clear();
     MessageLoop::current()->Quit();
   }
+  
+  MessageLoopForUI message_loop_;
 
   // PageUsageData vector to test segments.
   ScopedVector<PageUsageData> page_usage_data_;
diff --git a/chrome/browser/history/text_database_manager_unittest.cc b/chrome/browser/history/text_database_manager_unittest.cc
index 5ad7cdf..8b7c6b9 100644
--- a/chrome/browser/history/text_database_manager_unittest.cc
+++ b/chrome/browser/history/text_database_manager_unittest.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "base/file_util.h"
+#include "base/message_loop.h"
 #include "chrome/browser/history/text_database_manager.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -44,6 +45,8 @@ class TextDatabaseManagerTest : public testing::Test {
   void TearDown() {
     file_util::Delete(dir_, true);
   }
+  
+  MessageLoop message_loop_;
 
   // Directory containing the databases.
   std::wstring dir_;
diff --git a/chrome/browser/importer_unittest.cc b/chrome/browser/importer_unittest.cc
index 2470513..5dde26c 100644
--- a/chrome/browser/importer_unittest.cc
+++ b/chrome/browser/importer_unittest.cc
@@ -45,6 +45,7 @@ class ImporterTest : public testing::Test {
     ASSERT_FALSE(file_util::PathExists(test_path_));
   }
 
+  MessageLoopForUI message_loop_;
   std::wstring test_path_;
   std::wstring profile_path_;
   std::wstring app_path_;
diff --git a/chrome/browser/jankometer.cc b/chrome/browser/jankometer.cc
index 8ee411e..495b849 100644
--- a/chrome/browser/jankometer.cc
+++ b/chrome/browser/jankometer.cc
@@ -73,7 +73,7 @@ class JankWatchdog : public Watchdog {
 
 //------------------------------------------------------------------------------
 class JankObserver : public base::RefCountedThreadSafe<JankObserver>,
-                     public MessageLoop::Observer {
+                     public MessageLoopForUI::Observer {
  public:
   JankObserver(const wchar_t* thread_name,
                const TimeDelta& excessive_duration,
@@ -95,12 +95,15 @@ class JankObserver : public base::RefCountedThreadSafe<JankObserver>,
   // attach to the current thread, so this function can be invoked on another
   // thread to attach it.
   void AttachToCurrentThread() {
-    MessageLoop::current()->AddObserver(this);
+    // TODO(darin): support monitoring jankiness on non-UI threads!
+    if (MessageLoop::current()->type() == MessageLoop::TYPE_UI)
+      MessageLoopForUI::current()->AddObserver(this);
   }
 
   // Detaches the observer to the current thread's message loop.
   void DetachFromCurrentThread() {
-    MessageLoop::current()->RemoveObserver(this);
+    if (MessageLoop::current()->type() == MessageLoop::TYPE_UI)
+      MessageLoopForUI::current()->RemoveObserver(this);
   }
 
   void WillProcessMessage(const MSG& msg) {
@@ -200,7 +203,7 @@ void InstallJankometer(const CommandLine &parsed_command_line) {
       TimeDelta::FromMilliseconds(kMaxIOMessageDelayMs),
       io_watchdog_enabled);
   io_observer->AddRef();
-  Thread* io_thread = g_browser_process->io_thread();
+  base::Thread* io_thread = g_browser_process->io_thread();
   if (io_thread) {
     io_thread->message_loop()->PostTask(FROM_HERE,
         NewRunnableMethod(io_observer,
diff --git a/chrome/browser/navigation_controller_unittest.cc b/chrome/browser/navigation_controller_unittest.cc
index 72d2e5c..fa5e3e4 100644
--- a/chrome/browser/navigation_controller_unittest.cc
+++ b/chrome/browser/navigation_controller_unittest.cc
@@ -164,6 +164,9 @@ class NavigationControllerTest : public testing::Test,
   TestContents* contents;
 
   Profile* profile;
+ 
+ private:
+  MessageLoopForUI message_loop_;
 };
 
 // NavigationControllerHistoryTest ---------------------------------------------
diff --git a/chrome/browser/network_status_view.cc b/chrome/browser/network_status_view.cc
index 296d46e..4a0e57c 100644
--- a/chrome/browser/network_status_view.cc
+++ b/chrome/browser/network_status_view.cc
@@ -156,7 +156,7 @@ NetworkStatusView::JobTracker::JobTracker(NetworkStatusView* view)
 
 // main thread:
 void NetworkStatusView::JobTracker::InvokeOnIOThread(void (JobTracker::*m)()) {
-  Thread* thread = g_browser_process->io_thread();
+  base::Thread* thread = g_browser_process->io_thread();
   if (!thread)
     return;
   thread->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(this, m));
diff --git a/chrome/browser/printing/print_job_worker.h b/chrome/browser/printing/print_job_worker.h
index 0509a0f..3e25ec5 100644
--- a/chrome/browser/printing/print_job_worker.h
+++ b/chrome/browser/printing/print_job_worker.h
@@ -23,7 +23,7 @@ class PrintJobWorkerOwner;
 // NOTIFY_PRINT_JOB_EVENT notifications, but they are generated through a
 // NotificationTask task to be executed from the right thread, the UI thread.
 // PrintJob always outlives its worker instance.
-class PrintJobWorker : public Thread {
+class PrintJobWorker : public base::Thread {
  public:
   PrintJobWorker(PrintJobWorkerOwner* owner);
   ~PrintJobWorker();
diff --git a/chrome/browser/printing/printer_query.h b/chrome/browser/printing/printer_query.h
index 0cbffbf..d79ac73 100644
--- a/chrome/browser/printing/printer_query.h
+++ b/chrome/browser/printing/printer_query.h
@@ -11,7 +11,10 @@
 
 class CancelableTask;
 class MessageLoop;
+
+namespace base {
 class Thread;
+}
 
 namespace printing {
 
diff --git a/chrome/browser/printing/printing_layout_uitest.cc b/chrome/browser/printing/printing_layout_uitest.cc
index 2151824..30e1c75 100644
--- a/chrome/browser/printing/printing_layout_uitest.cc
+++ b/chrome/browser/printing/printing_layout_uitest.cc
@@ -559,7 +559,8 @@ TEST_F(PrintingLayoutTest, DISABLED_Delayed) {
               tab_proxy->NavigateToURL(url));
 
 
-    scoped_ptr<Thread> worker(new Thread("PrintingLayoutTest_worker"));
+    scoped_ptr<base::Thread> worker(
+        new base::Thread("PrintingLayoutTest_worker"));
     DismissTheWindow dismiss_task(process_util::GetProcId(process()));
     // We need to start the thread to be able to set the timer.
     worker->Start();
@@ -597,7 +598,8 @@ TEST_F(PrintingLayoutTest, DISABLED_IFrame) {
     EXPECT_EQ(AUTOMATION_MSG_NAVIGATION_SUCCESS,
               tab_proxy->NavigateToURL(url));
 
-    scoped_ptr<Thread> worker(new Thread("PrintingLayoutTest_worker"));
+    scoped_ptr<base::Thread> worker(
+        new base::Thread("PrintingLayoutTest_worker"));
     DismissTheWindow dismiss_task(process_util::GetProcId(process()));
     // We need to start the thread to be able to set the timer.
     worker->Start();
diff --git a/chrome/browser/profile.cc b/chrome/browser/profile.cc
index 857dd21..e974e2a 100644
--- a/chrome/browser/profile.cc
+++ b/chrome/browser/profile.cc
@@ -598,7 +598,7 @@ ProfileImpl::~ProfileImpl() {
     history_service_->Cleanup();
 
   // The I/O thread may be NULL during testing.
-  Thread* io_thread = g_browser_process->io_thread();
+  base::Thread* io_thread = g_browser_process->io_thread();
 
   if (spellchecker_) {
     // The spellchecker must be deleted on the I/O thread. During testing, we
diff --git a/chrome/browser/profile_manager_unittest.cc b/chrome/browser/profile_manager_unittest.cc
index bcc844e..8a7ed05 100644
--- a/chrome/browser/profile_manager_unittest.cc
+++ b/chrome/browser/profile_manager_unittest.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "base/file_util.h"
+#include "base/message_loop.h"
 #include "base/path_service.h"
 #include "chrome/browser/profile.h"
 #include "chrome/browser/profile_manager.h"
@@ -29,6 +30,8 @@ protected:
     ASSERT_TRUE(file_util::Delete(test_dir_, true));
     ASSERT_FALSE(file_util::PathExists(test_dir_));
   }
+  
+  MessageLoopForUI message_loop_;
 
   // the path to temporary directory used to contain the test operations
   std::wstring test_dir_;
diff --git a/chrome/browser/render_process_host.cc b/chrome/browser/render_process_host.cc
index 0973fec..c18b4f3 100644
--- a/chrome/browser/render_process_host.cc
+++ b/chrome/browser/render_process_host.cc
@@ -85,10 +85,10 @@ unsigned int GetMaxRendererProcessCount() {
 
 // ----------------------------------------------------------------------------
 
-class RendererMainThread : public Thread {
+class RendererMainThread : public base::Thread {
  public:
   explicit RendererMainThread(const std::wstring& channel_id)
-      : Thread("Chrome_InProcRendererThread"),
+      : base::Thread("Chrome_InProcRendererThread"),
         channel_id_(channel_id) {
   }
 
@@ -103,7 +103,7 @@ class RendererMainThread : public Thread {
     // this thread, so just force the flag manually.
     // If we want to avoid this, we could create the InProcRendererThread
     // directly with _beginthreadex() rather than using the Thread class.
-    Thread::SetThreadWasQuitProperly(true);
+    base::Thread::SetThreadWasQuitProperly(true);
   }
 
   virtual void CleanUp() {
@@ -201,7 +201,7 @@ bool RenderProcessHost::Init() {
     return true;
 
   // run the IPC channel on the shared IO thread.
-  Thread* io_thread = g_browser_process->io_thread();
+  base::Thread* io_thread = g_browser_process->io_thread();
 
   scoped_refptr<ResourceMessageFilter> resource_message_filter =
       new ResourceMessageFilter(g_browser_process->resource_dispatcher_host(),
@@ -306,22 +306,22 @@ bool RenderProcessHost::Init() {
 
   bool run_in_process = RenderProcessHost::run_renderer_in_process();
   if (run_in_process) {
-    // Crank up a thread and run the initialization there.  With the
-    // way that messages flow between the browser and renderer, this
-    // thread is required to prevent a deadlock in single-process mode.
-    // When using multiple processes, the primordial thread in the
-    // renderer process has a message loop which is used for sending
-    // messages asynchronously to the io thread in the browser process.
-    // If we don't create this thread, then the RenderThread is both
-    // responsible for rendering and also for communicating IO.
-    // This can lead to deadlocks where the RenderThread is waiting
-    // for the IO to complete, while the browsermain is trying to
-    // pass an event to the RenderThread.
+    // Crank up a thread and run the initialization there.  With the way that
+    // messages flow between the browser and renderer, this thread is required
+    // to prevent a deadlock in single-process mode.  When using multiple
+    // processes, the primordial thread in the renderer process has a message
+    // loop which is used for sending messages asynchronously to the io thread
+    // in the browser process.  If we don't create this thread, then the
+    // RenderThread is both responsible for rendering and also for
+    // communicating IO.  This can lead to deadlocks where the RenderThread is
+    // waiting for the IO to complete, while the browsermain is trying to pass
+    // an event to the RenderThread.
     //
-    // TODO: We should consider how to better cleanup threads on
-    // exit.
-    Thread *renderThread = new RendererMainThread(channel_id);
-    renderThread->Start();
+    // TODO: We should consider how to better cleanup threads on exit.
+    base::Thread *render_thread = new RendererMainThread(channel_id);
+    base::Thread::Options options;
+    options.message_loop_type = MessageLoop::TYPE_IO;
+    render_thread->StartWithOptions(options);
   } else {
     if (g_browser_process->local_state() &&
         g_browser_process->local_state()->GetBoolean(
diff --git a/chrome/browser/render_process_host.h b/chrome/browser/render_process_host.h
index 76bdb10..f725544 100644
--- a/chrome/browser/render_process_host.h
+++ b/chrome/browser/render_process_host.h
@@ -23,9 +23,12 @@
 class PrefService;
 class Profile;
 class RenderWidgetHelper;
-class Thread;
 class WebContents;
 
+namespace base {
+class Thread;
+}
+
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 //
diff --git a/chrome/browser/resource_dispatcher_host_unittest.cc b/chrome/browser/resource_dispatcher_host_unittest.cc
index 3291cea..101e9f7 100644
--- a/chrome/browser/resource_dispatcher_host_unittest.cc
+++ b/chrome/browser/resource_dispatcher_host_unittest.cc
@@ -115,6 +115,7 @@ class ResourceDispatcherHostTest : public testing::Test,
     }
   }
 
+  MessageLoopForIO message_loop_;
   ResourceDispatcherHost host_;
   ResourceIPCAccumulator accum_;
 };
diff --git a/chrome/browser/resource_message_filter.cc b/chrome/browser/resource_message_filter.cc
index 073741c..d349839 100644
--- a/chrome/browser/resource_message_filter.cc
+++ b/chrome/browser/resource_message_filter.cc
@@ -654,7 +654,7 @@ class SpellCheckTask : public Task {
     if (checker)
       checker->SpellCheckWord(word_.c_str(), static_cast<int>(word_.length()),
                               &misspell_location, &misspell_length, NULL);
-    Thread* io_thread = g_browser_process->io_thread();
+    base::Thread* io_thread = g_browser_process->io_thread();
     if (io_thread) {
       io_thread->message_loop()->PostTask(FROM_HERE,
           new SpellCheckReplyTask(filter_, reply_msg_,
diff --git a/chrome/browser/rlz/rlz.cc b/chrome/browser/rlz/rlz.cc
index 6cc8d70..b319626 100644
--- a/chrome/browser/rlz/rlz.cc
+++ b/chrome/browser/rlz/rlz.cc
@@ -168,7 +168,7 @@ class DelayedInitTask : public Task {
       }
     }
     // Schedule the daily RLZ ping.
-    Thread* thread = g_browser_process->file_thread();
+    base::Thread* thread = g_browser_process->file_thread();
     if (thread)
       thread->message_loop()->PostTask(FROM_HERE, new DailyPingTask());
   }
diff --git a/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc b/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
index a4068fa..eacbf86 100644
--- a/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
@@ -325,7 +325,7 @@ void SafeBrowsingBlockingPage::NotifyDone() {
     tab_->AsWebContents()->set_interstitial_delegate(NULL);
   }
 
-  Thread* io_thread = g_browser_process->io_thread();
+  base::Thread* io_thread = g_browser_process->io_thread();
   if (!io_thread)
     return;
 
diff --git a/chrome/browser/safe_browsing/safe_browsing_service.cc b/chrome/browser/safe_browsing/safe_browsing_service.cc
index a9e526b..11cfad0 100644
--- a/chrome/browser/safe_browsing/safe_browsing_service.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_service.cc
@@ -50,7 +50,7 @@ void SafeBrowsingService::Initialize(MessageLoop* io_loop) {
 // the user checks the "Enable SafeBrowsing" option in the Advanced options UI.
 void SafeBrowsingService::Start() {
   DCHECK(!db_thread_.get());
-  db_thread_.reset(new Thread("Chrome_SafeBrowsingThread"));
+  db_thread_.reset(new base::Thread("Chrome_SafeBrowsingThread"));
   if (!db_thread_->Start())
     return;
 
diff --git a/chrome/browser/safe_browsing/safe_browsing_service.h b/chrome/browser/safe_browsing/safe_browsing_service.h
index 1f373e5..fe7d0e7 100644
--- a/chrome/browser/safe_browsing/safe_browsing_service.h
+++ b/chrome/browser/safe_browsing/safe_browsing_service.h
@@ -243,7 +243,7 @@ class SafeBrowsingService
   bool enabled_;
 
   // The SafeBrowsing thread that runs database operations.
-  scoped_ptr<Thread> db_thread_;
+  scoped_ptr<base::Thread> db_thread_;
 
   // Indicates if we are in the process of resetting the database.
   bool resetting_;
diff --git a/chrome/browser/save_file_manager.cc b/chrome/browser/save_file_manager.cc
index 6fb2524..e8537a7 100644
--- a/chrome/browser/save_file_manager.cc
+++ b/chrome/browser/save_file_manager.cc
@@ -39,7 +39,7 @@ SaveFileManager::SaveFileManager(MessageLoop* ui_loop,
   // on a non-UI thread can cause crashes during shutdown.
   DCHECK(ui_loop_ == MessageLoop::current());
   // Cache the message loop of file thread.
-  Thread* thread = g_browser_process->file_thread();
+  base::Thread* thread = g_browser_process->file_thread();
   if (thread)
     file_loop_ = thread->message_loop();
   else
diff --git a/chrome/browser/save_package.h b/chrome/browser/save_package.h
index 6ab00fb..29a22b9 100644
--- a/chrome/browser/save_package.h
+++ b/chrome/browser/save_package.h
@@ -40,11 +40,14 @@ class MessageLoop;
 class PrefService;
 class Profile;
 class WebContents;
-class Thread;
 class URLRequestContext;
 class WebContents;
 class Time;
 
+namespace base {
+class Thread;
+}
+
 // save package: manages all save item.
 class SavePackage : public base::RefCountedThreadSafe<SavePackage> {
  public:
diff --git a/chrome/browser/session_service.h b/chrome/browser/session_service.h
index d1b6e36..3f7548f 100644
--- a/chrome/browser/session_service.h
+++ b/chrome/browser/session_service.h
@@ -24,11 +24,14 @@ class NavigationController;
 class NavigationEntry;
 class Profile;
 class TabContents;
-class Thread;
 class Timer;
 class SessionBackend;
 class SessionCommand;
 
+namespace base {
+class Thread;
+}
+
 // TabNavigation  ------------------------------------------------------------
 
 // TabNavigation corresponds to a NavigationEntry.
@@ -551,7 +554,7 @@ class SessionService : public CancelableRequestProvider,
 
   // Thread backend tasks are run on. This comes from the profile, and is
   // null during testing.
-  Thread* backend_thread_;
+  base::Thread* backend_thread_;
 
   // Are there any open open tabbed browsers?
   bool has_open_tabbed_browsers_;
diff --git a/chrome/browser/site_instance_unittest.cc b/chrome/browser/site_instance_unittest.cc
index 12eb0dc..4059fb4 100644
--- a/chrome/browser/site_instance_unittest.cc
+++ b/chrome/browser/site_instance_unittest.cc
@@ -9,7 +9,12 @@
 #include "chrome/test/testing_profile.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
-typedef testing::Test SiteInstanceTest;
+namespace {
+
+class SiteInstanceTest : public testing::Test {
+ private:
+  MessageLoopForUI message_loop_;
+};
 
 class TestBrowsingInstance : public BrowsingInstance {
  public:
@@ -55,8 +60,10 @@ class TestSiteInstance : public SiteInstance {
   int* deleteCounter_;
 };
 
+}  // namespace
+
 // Test to ensure no memory leaks for SiteInstance objects.
-TEST(SiteInstanceTest, SiteInstanceDestructor) {
+TEST_F(SiteInstanceTest, SiteInstanceDestructor) {
   int siteDeleteCounter = 0;
   int browsingDeleteCounter = 0;
   const GURL url("test:foo");
@@ -114,7 +121,7 @@ TEST(SiteInstanceTest, SiteInstanceDestructor) {
 // Test that NavigationEntries with SiteInstances can be cloned, but that their
 // SiteInstances can be changed afterwards.  Also tests that the ref counts are
 // updated properly after the change.
-TEST(SiteInstanceTest, CloneNavigationEntry) {
+TEST_F(SiteInstanceTest, CloneNavigationEntry) {
   int siteDeleteCounter1 = 0;
   int siteDeleteCounter2 = 0;
   int browsingDeleteCounter = 0;
@@ -153,7 +160,7 @@ TEST(SiteInstanceTest, CloneNavigationEntry) {
 }
 
 // Test to ensure UpdateMaxPageID is working properly.
-TEST(SiteInstanceTest, UpdateMaxPageID) {
+TEST_F(SiteInstanceTest, UpdateMaxPageID) {
   scoped_refptr<SiteInstance> instance(SiteInstance::CreateSiteInstance(NULL));
   EXPECT_EQ(-1, instance.get()->max_page_id());
 
@@ -164,7 +171,7 @@ TEST(SiteInstanceTest, UpdateMaxPageID) {
 }
 
 // Test to ensure GetProcess returns and creates processes correctly.
-TEST(SiteInstanceTest, GetProcess) {
+TEST_F(SiteInstanceTest, GetProcess) {
   // Ensure that GetProcess returns the process based on its host id.
   scoped_ptr<TestingProfile> profile(new TestingProfile());
   scoped_ptr<RenderProcessHost> host1(new RenderProcessHost(profile.get()));
@@ -181,7 +188,7 @@ TEST(SiteInstanceTest, GetProcess) {
 }
 
 // Test to ensure SetSite and site() work properly.
-TEST(SiteInstanceTest, SetSite) {
+TEST_F(SiteInstanceTest, SetSite) {
   scoped_refptr<SiteInstance> instance(SiteInstance::CreateSiteInstance(NULL));
   EXPECT_FALSE(instance->has_site());
   EXPECT_TRUE(instance.get()->site().is_empty());
@@ -193,7 +200,7 @@ TEST(SiteInstanceTest, SetSite) {
 }
 
 // Test to ensure GetSiteForURL properly returns sites for URLs.
-TEST(SiteInstanceTest, GetSiteForURL) {
+TEST_F(SiteInstanceTest, GetSiteForURL) {
   GURL test_url = GURL("http://www.google.com/index.html");
   EXPECT_EQ(GURL("http://google.com"), SiteInstance::GetSiteForURL(test_url));
 
@@ -220,7 +227,7 @@ TEST(SiteInstanceTest, GetSiteForURL) {
 // Test of distinguishing URLs from different sites.  Most of this logic is
 // tested in RegistryControlledDomainTest.  This test focuses on URLs with
 // different schemes or ports.
-TEST(SiteInstanceTest, IsSameWebSite) {
+TEST_F(SiteInstanceTest, IsSameWebSite) {
   GURL url_foo = GURL("http://foo/a.html");
   GURL url_foo2 = GURL("http://foo/b.html");
   GURL url_foo_https = GURL("https://foo/a.html");
@@ -247,7 +254,7 @@ TEST(SiteInstanceTest, IsSameWebSite) {
 
 // Test to ensure that there is only one SiteInstance per site in a given
 // BrowsingInstance, when process-per-site is not in use.
-TEST(SiteInstanceTest, OneSiteInstancePerSite) {
+TEST_F(SiteInstanceTest, OneSiteInstancePerSite) {
   int deleteCounter = 0;
   TestBrowsingInstance* browsing_instance =
       new TestBrowsingInstance(NULL, &deleteCounter);
@@ -305,7 +312,7 @@ TEST(SiteInstanceTest, OneSiteInstancePerSite) {
 
 // Test to ensure that there is only one SiteInstance per site for an entire
 // Profile, if process-per-site is in use.
-TEST(SiteInstanceTest, OneSiteInstancePerSiteInProfile) {
+TEST_F(SiteInstanceTest, OneSiteInstancePerSiteInProfile) {
   int deleteCounter = 0;
   TestBrowsingInstance* browsing_instance =
       new TestBrowsingInstance(NULL, &deleteCounter);
diff --git a/chrome/browser/spellchecker.cc b/chrome/browser/spellchecker.cc
index 25109b4..331b342 100644
--- a/chrome/browser/spellchecker.cc
+++ b/chrome/browser/spellchecker.cc
@@ -164,7 +164,7 @@ class UIProxyForIOTask : public Task {
  private:
   void Run() {
     // This has been invoked in the UI thread.
-    Thread* io_thread = g_browser_process->io_thread();
+    base::Thread* io_thread = g_browser_process->io_thread();
     if (io_thread) {  // io_thread has not been torn down yet.
       MessageLoop* io_loop = io_thread->message_loop();
       if (io_loop) {
@@ -214,7 +214,7 @@ SpellChecker::SpellChecker(const std::wstring& dict_dir,
   ui_loop_ = MessageLoop::current();
 
   // Get File Loop - hunspell gets initialized here.
-  Thread* file_thread = g_browser_process->file_thread();
+  base::Thread* file_thread = g_browser_process->file_thread();
   if (file_thread)
     file_loop_ = file_thread->message_loop();
 
diff --git a/chrome/browser/tabs/dragged_tab_controller.cc b/chrome/browser/tabs/dragged_tab_controller.cc
index eff01a4..80cbe65 100644
--- a/chrome/browser/tabs/dragged_tab_controller.cc
+++ b/chrome/browser/tabs/dragged_tab_controller.cc
@@ -96,13 +96,13 @@ DraggedTabController::DraggedTabController(Tab* source_tab,
   ChangeDraggedContents(
       source_tabstrip_->model()->GetTabContentsAt(source_model_index_));
   // Listen for Esc key presses.
-  MessageLoop::current()->AddObserver(this);
+  MessageLoopForUI::current()->AddObserver(this);
 }
 
 DraggedTabController::~DraggedTabController() {
   in_destructor_ = true;
   CleanUpSourceTab();
-  MessageLoop::current()->RemoveObserver(this);
+  MessageLoopForUI::current()->RemoveObserver(this);
   ChangeDraggedContents(NULL); // This removes our observer.
 }
 
diff --git a/chrome/browser/tabs/dragged_tab_controller.h b/chrome/browser/tabs/dragged_tab_controller.h
index 2485cf5..031a6ed 100644
--- a/chrome/browser/tabs/dragged_tab_controller.h
+++ b/chrome/browser/tabs/dragged_tab_controller.h
@@ -35,7 +35,7 @@ class TabStripModel;
 ///////////////////////////////////////////////////////////////////////////////
 class DraggedTabController : public TabContentsDelegate,
                              public NotificationObserver,
-                             public MessageLoop::Observer{
+                             public MessageLoopForUI::Observer{
  public:
   DraggedTabController(Tab* source_tab, TabStrip* source_tabstrip);
   virtual ~DraggedTabController();
diff --git a/chrome/browser/tabs/tab_strip.cc b/chrome/browser/tabs/tab_strip.cc
index aed87a1..b012443 100644
--- a/chrome/browser/tabs/tab_strip.cc
+++ b/chrome/browser/tabs/tab_strip.cc
@@ -1195,14 +1195,14 @@ bool TabStrip::IsCursorInTabStripZone() {
 
 void TabStrip::AddMessageLoopObserver() {
   if (!added_as_message_loop_observer_) {
-    MessageLoop::current()->AddObserver(this);
+    MessageLoopForUI::current()->AddObserver(this);
     added_as_message_loop_observer_ = true;
   }
 }
 
 void TabStrip::RemoveMessageLoopObserver() {
   if (added_as_message_loop_observer_) {
-    MessageLoop::current()->RemoveObserver(this);
+    MessageLoopForUI::current()->RemoveObserver(this);
     added_as_message_loop_observer_ = false;
   }
 }
diff --git a/chrome/browser/tabs/tab_strip.h b/chrome/browser/tabs/tab_strip.h
index ad14213..930b60b 100644
--- a/chrome/browser/tabs/tab_strip.h
+++ b/chrome/browser/tabs/tab_strip.h
@@ -41,7 +41,7 @@ class TabStrip : public ChromeViews::View,
                  public Tab::TabDelegate,
                  public ChromeViews::Button::ButtonListener,
                  public Task,
-                 public MessageLoop::Observer {
+                 public MessageLoopForUI::Observer {
  public:
   TabStrip(TabStripModel* model);
   virtual ~TabStrip();
diff --git a/chrome/browser/tabs/tab_strip_model_unittest.cc b/chrome/browser/tabs/tab_strip_model_unittest.cc
index e572835..9565f67 100644
--- a/chrome/browser/tabs/tab_strip_model_unittest.cc
+++ b/chrome/browser/tabs/tab_strip_model_unittest.cc
@@ -139,6 +139,7 @@ class TabStripModelTest : public testing::Test {
  Profile* profile_;
 
  private:
+  MessageLoopForUI message_loop_;
   std::wstring test_dir_;
   std::wstring profile_path_;
   ProfileManager pm_;
diff --git a/chrome/browser/task_manager.cc b/chrome/browser/task_manager.cc
index 6e240e0..b2e9798 100644
--- a/chrome/browser/task_manager.cc
+++ b/chrome/browser/task_manager.cc
@@ -234,7 +234,7 @@ void TaskManagerTableModel::StartUpdating() {
 
   // Register jobs notifications so we can compute network usage (it must be
   // done from the IO thread).
-  Thread* thread = g_browser_process->io_thread();
+  base::Thread* thread = g_browser_process->io_thread();
   if (thread)
     thread->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
         this, &TaskManagerTableModel::RegisterForJobDoneNotifications));
@@ -260,7 +260,7 @@ void TaskManagerTableModel::StopUpdating() {
   }
 
   // Unregister jobs notification (must be done from the IO thread).
-  Thread* thread = g_browser_process->io_thread();
+  base::Thread* thread = g_browser_process->io_thread();
   if (thread)
     thread->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
         this, &TaskManagerTableModel::UnregisterForJobDoneNotifications));
diff --git a/chrome/browser/template_url_model_unittest.cc b/chrome/browser/template_url_model_unittest.cc
index 7491523..d0239df 100644
--- a/chrome/browser/template_url_model_unittest.cc
+++ b/chrome/browser/template_url_model_unittest.cc
@@ -191,6 +191,7 @@ class TemplateURLModelTest : public testing::Test,
     TemplateURLRef::google_base_url_ = new std::wstring(base_url);
   }
 
+  MessageLoopForUI message_loop_;
   scoped_ptr<TemplateURLModelTestingProfile> profile_;
   scoped_ptr<TestingTemplateURLModel> model_;
   int changed_count_;
diff --git a/chrome/browser/url_fetcher_unittest.cc b/chrome/browser/url_fetcher_unittest.cc
index aa6cb54..5ffe231 100644
--- a/chrome/browser/url_fetcher_unittest.cc
+++ b/chrome/browser/url_fetcher_unittest.cc
@@ -16,7 +16,7 @@ namespace {
 
   class URLFetcherTest : public testing::Test, public URLFetcher::Delegate {
    public:
-    URLFetcherTest() : main_loop_(MessageLoop::current()), fetcher_(NULL) { }
+    URLFetcherTest() : fetcher_(NULL) { }
 
     // Creates a URLFetcher, using the program's main thread to do IO.
     virtual void CreateFetcher(const GURL& url);
@@ -30,7 +30,12 @@ namespace {
                                     const std::string& data);
 
    protected:
-    MessageLoop* main_loop_;
+    // URLFetcher is designed to run on the main UI thread, but in our tests
+    // we assume that the current thread is the IO thread where the URLFetcher
+    // dispatches its requests to.  When we wish to simulate being used from
+    // a UI thread, we dispatch a worker thread to do so.
+    MessageLoopForIO io_loop_;
+
     URLFetcher* fetcher_;
   };
 
@@ -114,7 +119,7 @@ namespace {
   void URLFetcherTest::CreateFetcher(const GURL& url) {
     fetcher_ = new URLFetcher(url, URLFetcher::GET, this);
     fetcher_->set_request_context(new TestURLRequestContext());
-    fetcher_->set_io_loop(main_loop_);
+    fetcher_->set_io_loop(&io_loop_);
     fetcher_->Start();
   }
 
@@ -132,8 +137,8 @@ namespace {
                       // because the destructor won't necessarily run on the
                       // same thread that CreateFetcher() did.
 
-    main_loop_->PostTask(FROM_HERE, new MessageLoop::QuitTask());
-    // If MessageLoop::current() != main_loop_, it will be shut down when the
+    io_loop_.PostTask(FROM_HERE, new MessageLoop::QuitTask());
+    // If MessageLoop::current() != io_loop_, it will be shut down when the
     // main loop returns and this thread subsequently goes out of scope.
   }
 
@@ -145,7 +150,7 @@ namespace {
   void URLFetcherPostTest::CreateFetcher(const GURL& url) {
     fetcher_ = new URLFetcher(url, URLFetcher::POST, this);
     fetcher_->set_request_context(new TestURLRequestContext());
-    fetcher_->set_io_loop(main_loop_);
+    fetcher_->set_io_loop(&io_loop_);
     fetcher_->set_upload_data("application/x-www-form-urlencoded",
                               "bobsyeruncle");
     fetcher_->Start();
@@ -180,7 +185,7 @@ namespace {
   void URLFetcherProtectTest::CreateFetcher(const GURL& url) {
     fetcher_ = new URLFetcher(url, URLFetcher::GET, this);
     fetcher_->set_request_context(new TestURLRequestContext());
-    fetcher_->set_io_loop(main_loop_);
+    fetcher_->set_io_loop(&io_loop_);
     start_time_ = Time::Now();
     fetcher_->Start();
   }
@@ -199,7 +204,7 @@ namespace {
       EXPECT_TRUE(status.is_success());
       EXPECT_FALSE(data.empty());
       delete fetcher_;
-     main_loop_->Quit();
+      io_loop_.Quit();
     } else {
       // Now running Overload test.
       static int count = 0;
@@ -243,7 +248,7 @@ namespace {
 
     // The rest is the same as URLFetcherTest::OnURLFetchComplete.
     delete fetcher_;
-    main_loop_->Quit();
+    io_loop_.Quit();
   }
 
   std::wstring URLFetcherBadHTTPSTest::GetExpiredCertPath() {
@@ -271,7 +276,7 @@ TEST_F(URLFetcherTest, DifferentThreadsTest) {
   // terminate the main thread's message loop; then the other thread's
   // message loop will be shut down automatically as the thread goes out of
   // scope.
-  Thread t("URLFetcher test thread");
+  base::Thread t("URLFetcher test thread");
   t.Start();
   t.message_loop()->PostTask(FROM_HERE, new FetcherWrapperTask(this,
       GURL(server.TestServerPage("defaultresponse"))));
diff --git a/chrome/browser/user_data_dir_dialog.cc b/chrome/browser/user_data_dir_dialog.cc
index 5c06cca..3859a5b 100644
--- a/chrome/browser/user_data_dir_dialog.cc
+++ b/chrome/browser/user_data_dir_dialog.cc
@@ -15,7 +15,7 @@ std::wstring UserDataDirDialog::RunUserDataDirDialog(
     const std::wstring& user_data_dir) {
   // When the window closes, it will delete itself.
   UserDataDirDialog* dlg = new UserDataDirDialog(user_data_dir);
-  MessageLoop::current()->Run(dlg);
+  MessageLoopForUI::current()->Run(dlg);
   return dlg->user_data_dir();
 }
 
diff --git a/chrome/browser/user_data_dir_dialog.h b/chrome/browser/user_data_dir_dialog.h
index dbdf55b..d9811a8 100644
--- a/chrome/browser/user_data_dir_dialog.h
+++ b/chrome/browser/user_data_dir_dialog.h
@@ -19,7 +19,7 @@ class Window;
 }
 
 class UserDataDirDialog : public ChromeViews::DialogDelegate,
-                          public MessageLoop::Dispatcher,
+                          public MessageLoopForUI::Dispatcher,
                           public SelectFileDialog::Listener {
  public:
   // Creates and runs a user data directory picker dialog.  The method blocks
diff --git a/chrome/browser/views/bookmark_editor_view_unittest.cc b/chrome/browser/views/bookmark_editor_view_unittest.cc
index e69e934..93a99bf 100644
--- a/chrome/browser/views/bookmark_editor_view_unittest.cc
+++ b/chrome/browser/views/bookmark_editor_view_unittest.cc
@@ -32,6 +32,7 @@ class BookmarkEditorViewTest : public testing::Test {
   }
 
  protected:
+  MessageLoopForUI message_loop_;
   BookmarkBarModel* model_;
   scoped_ptr<TestingProfile> profile_;
 
diff --git a/chrome/browser/views/keyword_editor_view_unittest.cc b/chrome/browser/views/keyword_editor_view_unittest.cc
index 84b3f0d..7afee5d 100644
--- a/chrome/browser/views/keyword_editor_view_unittest.cc
+++ b/chrome/browser/views/keyword_editor_view_unittest.cc
@@ -62,6 +62,7 @@ class KeywordEditorViewTest : public testing::Test,
   }
 
  protected:
+  MessageLoopForUI message_loop_;
   scoped_ptr<TestingProfile> profile_;
   scoped_ptr<KeywordEditorView> editor_;
   TemplateURLModel* model_;
diff --git a/chrome/browser/views/options/advanced_contents_view.cc b/chrome/browser/views/options/advanced_contents_view.cc
index 46a4521..c70d80e 100644
--- a/chrome/browser/views/options/advanced_contents_view.cc
+++ b/chrome/browser/views/options/advanced_contents_view.cc
@@ -957,7 +957,7 @@ NetworkSection::NetworkSection(Profile* profile)
 void NetworkSection::ButtonPressed(ChromeViews::NativeButton* sender) {
   if (sender == change_proxies_button_) {
     UserMetricsRecordAction(L"Options_ChangeProxies", NULL);
-    Thread* thread = g_browser_process->file_thread();
+    base::Thread* thread = g_browser_process->file_thread();
     DCHECK(thread);
     thread->message_loop()->PostTask(FROM_HERE, new OpenConnectionDialogTask);
   } else if (sender == enable_link_doctor_checkbox_) {
diff --git a/chrome/browser/views/shell_dialogs.cc b/chrome/browser/views/shell_dialogs.cc
index 02b57d9..10f0399 100644
--- a/chrome/browser/views/shell_dialogs.cc
+++ b/chrome/browser/views/shell_dialogs.cc
@@ -20,9 +20,9 @@
 #include "chrome/common/win_util.h"
 #include "generated_resources.h"
 
-class ShellDialogThread : public Thread {
+class ShellDialogThread : public base::Thread {
  public:
-  ShellDialogThread() : Thread("Chrome_ShellDialogThread") { }
+  ShellDialogThread() : base::Thread("Chrome_ShellDialogThread") { }
 
  protected:
   void Init() {
@@ -55,7 +55,7 @@ class BaseShellDialogImpl {
     HWND owner;
 
     // Thread dialog is run on.
-    Thread* dialog_thread;
+    base::Thread* dialog_thread;
   };
 
   // Called at the beginning of a modal dialog run. Disables the owner window
@@ -93,7 +93,7 @@ class BaseShellDialogImpl {
   // thread otherwise in some situations where a singleton owns a single
   // instance of this object we can have a situation where a modal dialog in
   // one window blocks the appearance of a modal dialog in another.
-  static Thread* CreateDialogThread();
+  static base::Thread* CreateDialogThread();
 
   // Enables the window |owner_|. Can only be run from the ui thread.
   void EnableOwner(HWND owner);
@@ -169,8 +169,8 @@ void BaseShellDialogImpl::DisableOwner(HWND owner) {
 }
 
 // static
-Thread* BaseShellDialogImpl::CreateDialogThread() {
-  Thread* thread = new ShellDialogThread;
+base::Thread* BaseShellDialogImpl::CreateDialogThread() {
+  base::Thread* thread = new ShellDialogThread;
   bool started = thread->Start();
   DCHECK(started);
   return thread;
diff --git a/chrome/browser/visitedlink_master.cc b/chrome/browser/visitedlink_master.cc
index ea68f22..ae307ab 100644
--- a/chrome/browser/visitedlink_master.cc
+++ b/chrome/browser/visitedlink_master.cc
@@ -199,13 +199,13 @@ class VisitedLinkMaster::TableBuilder : public HistoryService::URLEnumerator,
 
 // VisitedLinkMaster ----------------------------------------------------------
 
-VisitedLinkMaster::VisitedLinkMaster(Thread* file_thread,
+VisitedLinkMaster::VisitedLinkMaster(base::Thread* file_thread,
                                      PostNewTableEvent* poster,
                                      Profile* profile) {
   InitMembers(file_thread, poster, profile);
 }
 
-VisitedLinkMaster::VisitedLinkMaster(Thread* file_thread,
+VisitedLinkMaster::VisitedLinkMaster(base::Thread* file_thread,
                                      PostNewTableEvent* poster,
                                      HistoryService* history_service,
                                      bool suppress_rebuild,
@@ -230,7 +230,7 @@ VisitedLinkMaster::~VisitedLinkMaster() {
   FreeURLTable();
 }
 
-void VisitedLinkMaster::InitMembers(Thread* file_thread,
+void VisitedLinkMaster::InitMembers(base::Thread* file_thread,
                                     PostNewTableEvent* poster,
                                     Profile* profile) {
   if (file_thread)
diff --git a/chrome/browser/visitedlink_master.h b/chrome/browser/visitedlink_master.h
index 7935f69..56923a7 100644
--- a/chrome/browser/visitedlink_master.h
+++ b/chrome/browser/visitedlink_master.h
@@ -31,7 +31,7 @@ class VisitedLinkMaster : public VisitedLinkCommon {
 
   // The |file_thread| may be NULL, in which case write operations will be
   // synchronous.
-  VisitedLinkMaster(Thread* file_thread,
+  VisitedLinkMaster(base::Thread* file_thread,
                     PostNewTableEvent* poster,
                     Profile* profile);
 
@@ -50,7 +50,7 @@ class VisitedLinkMaster : public VisitedLinkCommon {
   // When |suppress_rebuild| is set, we'll not attempt to load data from
   // history if the file can't be loaded. This should generally be set for
   // testing except when you want to test the rebuild process explicitly.
-  VisitedLinkMaster(Thread* file_thread,
+  VisitedLinkMaster(base::Thread* file_thread,
                     PostNewTableEvent* poster,
                     HistoryService* history_service,
                     bool suppress_rebuild,
@@ -144,7 +144,7 @@ class VisitedLinkMaster : public VisitedLinkCommon {
   static const int32 kBigDeleteThreshold;
 
   // Backend for the constructors initializing the members.
-  void InitMembers(Thread* file_thread,
+  void InitMembers(base::Thread* file_thread,
                    PostNewTableEvent* poster,
                    Profile* profile);
 
diff --git a/chrome/browser/visitedlink_unittest.cc b/chrome/browser/visitedlink_unittest.cc
index 7f864b0..afad81c 100644
--- a/chrome/browser/visitedlink_unittest.cc
+++ b/chrome/browser/visitedlink_unittest.cc
@@ -144,6 +144,8 @@ class VisitedLinkTest : public testing::Test {
     ClearDB();
     file_util::Delete(history_dir_, true);
   }
+  
+  MessageLoop message_loop_;
 
   // Filenames for the services;
   std::wstring history_dir_;
diff --git a/chrome/browser/web_contents_unittest.cc b/chrome/browser/web_contents_unittest.cc
index 1929550..032e8eb 100644
--- a/chrome/browser/web_contents_unittest.cc
+++ b/chrome/browser/web_contents_unittest.cc
@@ -296,6 +296,9 @@ class WebContentsTest : public testing::Test {
 
   scoped_ptr<WebContentsTestingProfile> profile;
   TestWebContents* contents;
+
+ private:
+  MessageLoopForUI message_loop_;
 };
 
 // Test to make sure that title updates get stripped of whitespace
diff --git a/chrome/browser/webdata/web_data_service.cc b/chrome/browser/webdata/web_data_service.cc
index c3cbfb1..48eebd8 100644
--- a/chrome/browser/webdata/web_data_service.cc
+++ b/chrome/browser/webdata/web_data_service.cc
@@ -39,7 +39,7 @@ bool WebDataService::Init(const std::wstring& profile_path) {
 }
 
 bool WebDataService::InitWithPath(const std::wstring& path) {
-  thread_ = new Thread("Chrome_WebDataThread");
+  thread_ = new base::Thread("Chrome_WebDataThread");
 
   if (!thread_->Start()) {
     delete thread_;
diff --git a/chrome/browser/webdata/web_data_service.h b/chrome/browser/webdata/web_data_service.h
index 5fbe5a6..d7e428d 100644
--- a/chrome/browser/webdata/web_data_service.h
+++ b/chrome/browser/webdata/web_data_service.h
@@ -427,7 +427,7 @@ class WebDataService : public base::RefCountedThreadSafe<WebDataService> {
 
   void GetWebAppImagesImpl(GenericRequest<GURL>* request);
 
-  Thread* thread() { return thread_; }
+  base::Thread* thread() { return thread_; }
 
  private:
 
@@ -441,7 +441,7 @@ class WebDataService : public base::RefCountedThreadSafe<WebDataService> {
   int GetNextRequestHandle();
 
   // Our worker thread. All requests are processed from that thread.
-  Thread* thread_;
+  base::Thread* thread_;
 
   // Our database.
   WebDatabase* db_;
diff --git a/chrome/browser/xp_frame.cc b/chrome/browser/xp_frame.cc
index 5454b1a..fbe65ed 100644
--- a/chrome/browser/xp_frame.cc
+++ b/chrome/browser/xp_frame.cc
@@ -1021,7 +1021,7 @@ void XPFrame::OnSize(UINT param, const CSize& size) {
     RedrawWindow(root_view_.GetScheduledPaintRect(),
                  NULL,
                  RDW_UPDATENOW | RDW_INVALIDATE | RDW_ALLCHILDREN);
-    MessageLoop::current()->PumpOutPendingPaintMessages();
+    MessageLoopForUI::current()->PumpOutPendingPaintMessages();
   }
 
   if (!saved_window_placement_ && should_save_window_placement_)
diff --git a/chrome/common/animation_unittest.cc b/chrome/common/animation_unittest.cc
index e4429cd..3f9da3c 100644
--- a/chrome/common/animation_unittest.cc
+++ b/chrome/common/animation_unittest.cc
@@ -11,6 +11,8 @@ using namespace std;
 
 namespace {
   class AnimationTest: public testing::Test {
+   private:
+    MessageLoopForUI message_loop_;
   };
 };
 
@@ -81,7 +83,7 @@ class TestAnimationDelegate : public AnimationDelegate {
   bool canceled_;
 };
 
-TEST(AnimationTest, RunCase) {
+TEST_F(AnimationTest, RunCase) {
   TestAnimationDelegate ad;
   RunAnimation a1(150, &ad);
   a1.SetDuration(2000);
@@ -92,7 +94,7 @@ TEST(AnimationTest, RunCase) {
   EXPECT_FALSE(ad.canceled());
 }
 
-TEST(AnimationTest, CancelCase) {
+TEST_F(AnimationTest, CancelCase) {
   TestAnimationDelegate ad;
   CancelAnimation a2(2000, 150, &ad);
   a2.Start();
diff --git a/chrome/common/chrome_plugin_unittest.cc b/chrome/common/chrome_plugin_unittest.cc
index 139bcf4..f998755 100644
--- a/chrome/common/chrome_plugin_unittest.cc
+++ b/chrome/common/chrome_plugin_unittest.cc
@@ -62,6 +62,8 @@ class ChromePluginTest : public testing::Test, public URLRequest::Delegate {
     Profile::set_default_request_context(NULL);
   }
  protected:
+  MessageLoopForIO message_loop_;
+
   // Note: we use URLRequest (instead of URLFetcher) because this allows the
   // request to be intercepted.
   scoped_ptr<URLRequest> request_;
diff --git a/chrome/common/chrome_plugin_util.cc b/chrome/common/chrome_plugin_util.cc
index 1a33990..56b1f54 100644
--- a/chrome/common/chrome_plugin_util.cc
+++ b/chrome/common/chrome_plugin_util.cc
@@ -46,18 +46,14 @@ void PluginHelper::DestroyAllHelpersForPlugin(ChromePluginLib* plugin) {
 }
 
 PluginHelper::PluginHelper(ChromePluginLib* plugin) : plugin_(plugin) {
-#ifndef NDEBUG
-  message_loop_ = MessageLoop::current();
-#endif
+  DCHECK(CalledOnValidThread());
   NotificationService::current()->AddObserver(
       this, NOTIFY_CHROME_PLUGIN_UNLOADED,
       Source<ChromePluginLib>(plugin_));
 }
 
 PluginHelper::~PluginHelper() {
-#ifndef NDEBUG
-  DCHECK(MessageLoop::current() == message_loop_);
-#endif
+  DCHECK(CalledOnValidThread());
   NotificationService::current()->RemoveObserver(
       this, NOTIFY_CHROME_PLUGIN_UNLOADED,
       Source<ChromePluginLib>(plugin_));
@@ -66,9 +62,7 @@ PluginHelper::~PluginHelper() {
 void PluginHelper::Observe(NotificationType type,
                            const NotificationSource& source,
                            const NotificationDetails& details) {
-#ifndef NDEBUG
-  DCHECK(MessageLoop::current() == message_loop_);
-#endif
+  DCHECK(CalledOnValidThread());
   DCHECK(type == NOTIFY_CHROME_PLUGIN_UNLOADED);
   DCHECK(plugin_ == Source<ChromePluginLib>(source).ptr());
 
diff --git a/chrome/common/chrome_plugin_util.h b/chrome/common/chrome_plugin_util.h
index 847e096..5ca17fc 100644
--- a/chrome/common/chrome_plugin_util.h
+++ b/chrome/common/chrome_plugin_util.h
@@ -6,6 +6,7 @@
 #define CHROME_COMMON_CHROME_PLUGIN_UTIL_H__
 
 #include "base/basictypes.h"
+#include "base/non_thread_safe.h"
 #include "base/ref_counted.h"
 #include "chrome/common/chrome_plugin_api.h"
 #include "chrome/common/notification_service.h"
@@ -35,7 +36,7 @@ struct ScopableCPRequest : public CPRequest {
 // This is a base class for plugin-related objects that need to go away when
 // the plugin unloads.  This object also verifies that it is created and
 // destroyed on the same thread.
-class PluginHelper : public NotificationObserver {
+class PluginHelper : public NotificationObserver, public NonThreadSafe {
  public:
   static void DestroyAllHelpersForPlugin(ChromePluginLib* plugin);
 
@@ -49,11 +50,6 @@ class PluginHelper : public NotificationObserver {
 
  protected:
   scoped_refptr<ChromePluginLib> plugin_;
-#ifndef NDEBUG
-  // We keep track of the message loop of the thread we were created on, so
-  // we can verify that all other methods are called on the same thread.
-  MessageLoop* message_loop_;
-#endif
 
   DISALLOW_EVIL_CONSTRUCTORS(PluginHelper);
 };
diff --git a/chrome/common/ipc_channel.cc b/chrome/common/ipc_channel.cc
index 40a101b..c87d75f 100644
--- a/chrome/common/ipc_channel.cc
+++ b/chrome/common/ipc_channel.cc
@@ -49,8 +49,9 @@ Channel::Channel(const wstring& channel_id, Mode mode, Listener* listener)
 
 void Channel::Close() {
   // make sure we are no longer watching the pipe events
-  MessageLoop::current()->WatchObject(input_state_.overlapped.hEvent, NULL);
-  MessageLoop::current()->WatchObject(output_state_.overlapped.hEvent, NULL);
+  MessageLoopForIO* loop = MessageLoopForIO::current();
+  loop->WatchObject(input_state_.overlapped.hEvent, NULL);
+  loop->WatchObject(output_state_.overlapped.hEvent, NULL);
 
   if (pipe_ != INVALID_HANDLE_VALUE) {
     CloseHandle(pipe_);
@@ -168,7 +169,8 @@ bool Channel::Connect() {
     // to OnObjectSignaled that this is the special initialization signal.
 
     SetEvent(input_state_.overlapped.hEvent);
-    MessageLoop::current()->WatchObject(input_state_.overlapped.hEvent, this);
+    MessageLoopForIO::current()->WatchObject(
+        input_state_.overlapped.hEvent, this);
   }
 
   if (!waiting_connect_)
@@ -178,7 +180,8 @@ bool Channel::Connect() {
 
 bool Channel::ProcessConnection() {
   input_state_.is_pending = false;
-  MessageLoop::current()->WatchObject(input_state_.overlapped.hEvent, NULL);
+  MessageLoopForIO::current()->WatchObject(
+      input_state_.overlapped.hEvent, NULL);
 
   // Do we have a client connected to our pipe?
   DCHECK(pipe_ != INVALID_HANDLE_VALUE);
@@ -195,7 +198,8 @@ bool Channel::ProcessConnection() {
   switch (err) {
   case ERROR_IO_PENDING:
     input_state_.is_pending = true;
-    MessageLoop::current()->WatchObject(input_state_.overlapped.hEvent, this);
+    MessageLoopForIO::current()->WatchObject(
+        input_state_.overlapped.hEvent, this);
     break;
   case ERROR_PIPE_CONNECTED:
     waiting_connect_ = false;
@@ -211,7 +215,8 @@ bool Channel::ProcessConnection() {
 bool Channel::ProcessIncomingMessages() {
   DWORD bytes_read = 0;
 
-  MessageLoop::current()->WatchObject(input_state_.overlapped.hEvent, NULL);
+  MessageLoopForIO::current()->WatchObject(
+      input_state_.overlapped.hEvent, NULL);
 
   if (input_state_.is_pending) {
     input_state_.is_pending = false;
@@ -243,8 +248,8 @@ bool Channel::ProcessIncomingMessages() {
       if (!ok) {
         DWORD err = GetLastError();
         if (err == ERROR_IO_PENDING) {
-          MessageLoop::current()->WatchObject(input_state_.overlapped.hEvent,
-                                              this);
+          MessageLoopForIO::current()->WatchObject(
+              input_state_.overlapped.hEvent, this);
           input_state_.is_pending = true;
           return true;
         }
@@ -307,7 +312,8 @@ bool Channel::ProcessOutgoingMessages() {
   DWORD bytes_written;
 
   if (output_state_.is_pending) {
-    MessageLoop::current()->WatchObject(output_state_.overlapped.hEvent, NULL);
+    MessageLoopForIO::current()->WatchObject(
+        output_state_.overlapped.hEvent, NULL);
     output_state_.is_pending = false;
     BOOL ok = GetOverlappedResult(pipe_,
                                   &output_state_.overlapped,
@@ -336,8 +342,8 @@ bool Channel::ProcessOutgoingMessages() {
     if (!ok) {
       DWORD err = GetLastError();
       if (err == ERROR_IO_PENDING) {
-        MessageLoop::current()->WatchObject(output_state_.overlapped.hEvent,
-                                            this);
+        MessageLoopForIO::current()->WatchObject(
+            output_state_.overlapped.hEvent, this);
         output_state_.is_pending = true;
 
 #ifdef IPC_MESSAGE_DEBUG_EXTRA
diff --git a/chrome/common/ipc_channel.h b/chrome/common/ipc_channel.h
index 549e9cb..94d41a3 100644
--- a/chrome/common/ipc_channel.h
+++ b/chrome/common/ipc_channel.h
@@ -14,7 +14,7 @@ namespace IPC {
 
 //------------------------------------------------------------------------------
 
-class Channel : public MessageLoop::Watcher,
+class Channel : public MessageLoopForIO::Watcher,
                 public Message::Sender {
   // Security tests need access to the pipe handle.
   friend class ChannelTest;
diff --git a/chrome/common/ipc_sync_channel_unittest.cc b/chrome/common/ipc_sync_channel_unittest.cc
index f930790..3899204 100644
--- a/chrome/common/ipc_sync_channel_unittest.cc
+++ b/chrome/common/ipc_sync_channel_unittest.cc
@@ -97,12 +97,13 @@ class Worker : public Channel::Listener, public Message::Sender {
   void WaitForChannelCreation() { channel_created_.Wait(); }
   void CloseChannel() { channel_.reset(); }
   void Start() {
-    listener_thread_.Start();
-    Thread* thread = overrided_thread_ ? overrided_thread_ : &listener_thread_;
+    StartThread(&listener_thread_);
+    base::Thread* thread =
+        overrided_thread_ ? overrided_thread_ : &listener_thread_;
     thread->message_loop()->PostTask(FROM_HERE, NewRunnableMethod(
         this, &Worker::OnStart));
   }
-  void OverrideThread(Thread* overrided_thread) {
+  void OverrideThread(base::Thread* overrided_thread) {
     DCHECK(overrided_thread_ == NULL);
     overrided_thread_ = overrided_thread;
   }
@@ -133,8 +134,8 @@ class Worker : public Channel::Listener, public Message::Sender {
  private:
   // Called on the listener thread to create the sync channel.
   void OnStart() {
-    ipc_thread_.Start();
     // Link ipc_thread_, listener_thread_ and channel_ altogether.
+    StartThread(&ipc_thread_);
     channel_.reset(new SyncChannel(
         channel_name_, mode_, this, NULL, ipc_thread_.message_loop(), true,
         TestProcess::GetShutDownEvent()));
@@ -150,14 +151,20 @@ class Worker : public Channel::Listener, public Message::Sender {
     IPC_END_MESSAGE_MAP()
   }
 
+  void StartThread(base::Thread* thread) {
+    base::Thread::Options options;
+    options.message_loop_type = MessageLoop::TYPE_IO;
+    thread->StartWithOptions(options);
+  }
+
   Event done_;
   Event channel_created_;
   std::wstring channel_name_;
   Channel::Mode mode_;
   scoped_ptr<SyncChannel> channel_;
-  Thread ipc_thread_;
-  Thread listener_thread_;
-  Thread* overrided_thread_;
+  base::Thread ipc_thread_;
+  base::Thread listener_thread_;
+  base::Thread* overrided_thread_;
 
   DISALLOW_EVIL_CONSTRUCTORS(Worker);
 };
@@ -191,6 +198,8 @@ void RunTest(std::vector<Worker*> workers) {
   int count = static_cast<int>(done_handles.size());
   WaitForMultipleObjects(count, &done_handles.front(), TRUE, INFINITE);
   STLDeleteContainerPointers(workers.begin(), workers.end());
+  
+  TestProcess::GlobalCleanup();
 }
 
 
@@ -403,7 +412,7 @@ TEST(IPCSyncChannelTest, Multiple) {
   std::vector<Worker*> workers;
 
   // A shared worker thread so that server1 and server2 run on one thread.
-  Thread worker_thread("Multiple");
+  base::Thread worker_thread("Multiple");
   worker_thread.Start();
 
   // Server1 sends a sync msg to client1, which blocks the reply until
@@ -510,7 +519,7 @@ TEST(IPCSyncChannelTest, QueuedReply) {
   std::vector<Worker*> workers;
 
   // A shared worker thread so that server1 and server2 run on one thread.
-  Thread worker_thread("QueuedReply");
+  base::Thread worker_thread("QueuedReply");
   worker_thread.Start();
 
   Event client1_msg_received, server2_can_reply;
diff --git a/chrome/common/ipc_tests.cc b/chrome/common/ipc_tests.cc
index 316c397..67d7140 100644
--- a/chrome/common/ipc_tests.cc
+++ b/chrome/common/ipc_tests.cc
@@ -133,8 +133,10 @@ TEST(IPCChannelTest, ChannelTest) {
 
 TEST(IPCChannelTest, ChannelProxyTest) {
   // The thread needs to out-live the ChannelProxy.
-  Thread thread("ChannelProxyTestServer");
-  thread.Start();
+  base::Thread thread("ChannelProxyTestServer");
+  base::Thread::Options options;
+  options.message_loop_type = MessageLoop::TYPE_IO;
+  thread.StartWithOptions(options);
   {
     // setup IPC channel proxy
     IPC::ChannelProxy chan(kTestClientChannel, IPC::Channel::MODE_SERVER,
@@ -380,7 +382,7 @@ int main(int argc, char** argv) {
   // the AtExitManager or else we will leak objects.
   base::AtExitManager at_exit_manager;  
 
-  MessageLoop main_message_loop;
+  MessageLoopForIO main_message_loop;
 
   // suppress standard crash dialogs and such unless a debugger is present.
   if (!IsDebuggerPresent()) {
diff --git a/chrome/common/pref_service.cc b/chrome/common/pref_service.cc
index dd55bdc..60ac6f2 100644
--- a/chrome/common/pref_service.cc
+++ b/chrome/common/pref_service.cc
@@ -178,7 +178,7 @@ void PrefService::ReloadPersistentPrefs() {
   }
 }
 
-bool PrefService::SavePersistentPrefs(Thread* thread) const {
+bool PrefService::SavePersistentPrefs(base::Thread* thread) const {
   DCHECK(!pref_filename_.empty());
   DCHECK(CalledOnValidThread());
 
@@ -202,7 +202,7 @@ bool PrefService::SavePersistentPrefs(Thread* thread) const {
   return true;
 }
 
-void PrefService::ScheduleSavePersistentPrefs(Thread* thread) {
+void PrefService::ScheduleSavePersistentPrefs(base::Thread* thread) {
   if (!save_preferences_factory_.empty())
     return;
 
diff --git a/chrome/common/pref_service.h b/chrome/common/pref_service.h
index 9b552f2..32c012f 100644
--- a/chrome/common/pref_service.h
+++ b/chrome/common/pref_service.h
@@ -28,7 +28,10 @@
 
 class NotificationObserver;
 class Preference;
+
+namespace base {
 class Thread;
+}
 
 class PrefService : public NonThreadSafe {
  public:
@@ -88,12 +91,12 @@ class PrefService : public NonThreadSafe {
   // (since it's on a different thread).  This should only be used if we need
   // to save immediately (basically, during shutdown).  Otherwise, you should
   // use ScheduleSavePersistentPrefs.
-  bool SavePersistentPrefs(Thread* thread) const;
+  bool SavePersistentPrefs(base::Thread* thread) const;
 
   // Starts a timer that ends up saving the preferences.  This helps to batch
   // together save requests that happen in a close time frame so we don't write
   // to disk too frequently.
-  void ScheduleSavePersistentPrefs(Thread* thread);
+  void ScheduleSavePersistentPrefs(base::Thread* thread);
 
   DictionaryValue* transient() { return transient_.get(); }
 
diff --git a/chrome/common/process_watcher.cc b/chrome/common/process_watcher.cc
index 8a9fadc..b8d78bd2 100644
--- a/chrome/common/process_watcher.cc
+++ b/chrome/common/process_watcher.cc
@@ -5,6 +5,7 @@
 #include "chrome/common/process_watcher.h"
 
 #include "base/message_loop.h"
+#include "base/object_watcher.h"
 #include "chrome/app/result_codes.h"
 #include "chrome/common/env_util.h"
 #include "chrome/common/env_vars.h"
@@ -14,10 +15,10 @@ static const int kWaitInterval = 2000;
 
 namespace {
 
-class TimerExpiredTask : public Task, public MessageLoop::Watcher {
+class TimerExpiredTask : public Task, public base::ObjectWatcher::Delegate {
  public:
   explicit TimerExpiredTask(ProcessHandle process) : process_(process) {
-    MessageLoop::current()->WatchObject(process_, this);
+    watcher_.StartWatching(process_, this);
   }
 
   virtual ~TimerExpiredTask() {
@@ -37,12 +38,9 @@ class TimerExpiredTask : public Task, public MessageLoop::Watcher {
   // MessageLoop::Watcher -----------------------------------------------------
 
   virtual void OnObjectSignaled(HANDLE object) {
-    if (MessageLoop::current()) {
-      // When we're called from our destructor, the message loop is in the
-      // process of being torn down.  Only touch the message loop if it is
-      // still running.
-      MessageLoop::current()->WatchObject(process_, NULL);  // Stop watching.
-    }
+    // When we're called from KillProcess, the ObjectWatcher may still be
+    // watching.  the process handle, so make sure it has stopped.
+    watcher_.StopWatching();
 
     CloseHandle(process_);
     process_ = NULL;
@@ -72,6 +70,8 @@ class TimerExpiredTask : public Task, public MessageLoop::Watcher {
   // The process that we are watching.
   ProcessHandle process_;
 
+  base::ObjectWatcher watcher_;
+
   DISALLOW_EVIL_CONSTRUCTORS(TimerExpiredTask);
 };
 
diff --git a/chrome/plugin/plugin_main.cc b/chrome/plugin/plugin_main.cc
index 25e8968..df2dbc1 100644
--- a/chrome/plugin/plugin_main.cc
+++ b/chrome/plugin/plugin_main.cc
@@ -15,6 +15,10 @@
 // mainline routine for running as the plugin process
 int PluginMain(CommandLine &parsed_command_line, int show_command,
                sandbox::TargetServices* target_services) {
+  // The main thread of the plugin services IO.
+  MessageLoopForIO main_message_loop;
+  PlatformThread::SetName("Chrome_PluginMain");
+
   CoInitialize(NULL);
   DLOG(INFO) << "Started plugin with " <<
     parsed_command_line.command_line_string();
diff --git a/chrome/plugin/plugin_thread.cc b/chrome/plugin/plugin_thread.cc
index 2b39ef5..25bd06d 100644
--- a/chrome/plugin/plugin_thread.cc
+++ b/chrome/plugin/plugin_thread.cc
@@ -31,7 +31,10 @@ PluginThread::PluginThread(PluginProcess* process,
   DCHECK(!plugin_thread_);
   plugin_thread_ = this;
 
-  Start();
+  // We need to run a UI message loop to support plugin execution.
+  base::Thread::Options options;
+  options.message_loop_type = MessageLoop::TYPE_UI;
+  StartWithOptions(options);
 }
 
 PluginThread::~PluginThread() {
diff --git a/chrome/plugin/plugin_thread.h b/chrome/plugin/plugin_thread.h
index f2bfb85..df4b67a 100644
--- a/chrome/plugin/plugin_thread.h
+++ b/chrome/plugin/plugin_thread.h
@@ -19,7 +19,7 @@ class NotificationService;
 // process and WebPluginDelegateStub in this thread through IPC messages.
 class PluginThread : public IPC::Channel::Listener,
                      public IPC::Message::Sender,
-                     public Thread {
+                     public base::Thread {
  public:
   PluginThread(PluginProcess *process, const std::wstring& channel_name);
   ~PluginThread();
diff --git a/chrome/renderer/render_thread.cc b/chrome/renderer/render_thread.cc
index 6b34176..fb70dd4 100644
--- a/chrome/renderer/render_thread.cc
+++ b/chrome/renderer/render_thread.cc
@@ -37,7 +37,13 @@ RenderThread::RenderThread(const std::wstring& channel_name)
       render_dns_master_(NULL),
       in_send_(0) {
   DCHECK(owner_loop_);
-  StartWithStackSize(kStackSize);
+  base::Thread::Options options;
+  options.stack_size = kStackSize;
+  // When we run plugins in process, we actually run them on the render thread,
+  // which means that we need to make the render thread pump UI events.
+  if (RenderProcess::ShouldLoadPluginsInProcess())
+    options.message_loop_type = MessageLoop::TYPE_UI;
+  StartWithOptions(options);
 }
 
 RenderThread::~RenderThread() {
diff --git a/chrome/renderer/render_thread.h b/chrome/renderer/render_thread.h
index 6a7d019..89b203f 100644
--- a/chrome/renderer/render_thread.h
+++ b/chrome/renderer/render_thread.h
@@ -32,7 +32,7 @@ class NotificationService;
 
 class RenderThread : public IPC::Channel::Listener,
                      public IPC::Message::Sender,
-                     public Thread {
+                     public base::Thread {
  public:
   RenderThread(const std::wstring& channel_name);
   ~RenderThread();
diff --git a/chrome/renderer/renderer_main.cc b/chrome/renderer/renderer_main.cc
index 59c4003..7a3e898 100644
--- a/chrome/renderer/renderer_main.cc
+++ b/chrome/renderer/renderer_main.cc
@@ -43,11 +43,12 @@ static void HandleRendererErrorTestParameters(const CommandLine& command_line) {
 
 // mainline routine for running as the Rendererer process
 int RendererMain(CommandLine &parsed_command_line, int show_command,
-                 sandbox::TargetServices* target_services)
-{
+                 sandbox::TargetServices* target_services) {
   StatsScope<StatsCounterTimer>
       startup_timer(chrome::Counters::renderer_main());
 
+  // The main thread of the renderer services IO.
+  MessageLoopForIO main_message_loop;
   PlatformThread::SetName("Chrome_RendererMain");
 
   CoInitialize(NULL);
diff --git a/chrome/test/automation/automation_proxy.cc b/chrome/test/automation/automation_proxy.cc
index 965d47c..1724f95 100644
--- a/chrome/test/automation/automation_proxy.cc
+++ b/chrome/test/automation/automation_proxy.cc
@@ -182,8 +182,11 @@ void AutomationProxy::InitializeChannelID() {
 }
 
 void AutomationProxy::InitializeThread() {
-  scoped_ptr<Thread> thread(new Thread("AutomationProxy_BackgroundThread"));
-  bool thread_result = thread->Start();
+  scoped_ptr<base::Thread> thread(
+      new base::Thread("AutomationProxy_BackgroundThread"));
+  base::Thread::Options options;
+  options.message_loop_type = MessageLoop::TYPE_IO;
+  bool thread_result = thread->StartWithOptions(options);
   DCHECK(thread_result);
   thread_.swap(thread);
 }
diff --git a/chrome/test/automation/automation_proxy.h b/chrome/test/automation/automation_proxy.h
index 39a0f1c..8491832 100644
--- a/chrome/test/automation/automation_proxy.h
+++ b/chrome/test/automation/automation_proxy.h
@@ -201,7 +201,7 @@ class AutomationProxy : public IPC::Channel::Listener,
   void InitializeHandleTracker();
 
   std::wstring channel_id_;
-  scoped_ptr<Thread> thread_;
+  scoped_ptr<base::Thread> thread_;
   scoped_ptr<IPC::ChannelProxy> channel_;
   scoped_ptr<AutomationHandleTracker> tracker_;
 
diff --git a/chrome/test/testing_browser_process.h b/chrome/test/testing_browser_process.h
index 57c076b..b7255d0 100644
--- a/chrome/test/testing_browser_process.h
+++ b/chrome/test/testing_browser_process.h
@@ -37,15 +37,15 @@ class TestingBrowserProcess : public BrowserProcess {
     return NULL;
   }
 
-  virtual Thread* io_thread() {
+  virtual base::Thread* io_thread() {
     return NULL;
   }
 
-  virtual Thread* file_thread() {
+  virtual base::Thread* file_thread() {
     return NULL;
   }
 
-  virtual Thread* db_thread() {
+  virtual base::Thread* db_thread() {
     return NULL;
   }
 
diff --git a/chrome/test/ui/run_all_unittests.cc b/chrome/test/ui/run_all_unittests.cc
index f4c0116..9b7ec72 100644
--- a/chrome/test/ui/run_all_unittests.cc
+++ b/chrome/test/ui/run_all_unittests.cc
@@ -7,10 +7,6 @@
 #include "chrome/test/ui/ui_test_suite.h"
 
 int main(int argc, char **argv) {
-  // Some tests may use base::Singleton<>, thus we need to instanciate
-  // the AtExitManager or else we will leak objects.
-  base::AtExitManager at_exit_manager;  
-
   PlatformThread::SetName("Tests_Main");
   return UITestSuite(argc, argv).Run();
 }
diff --git a/chrome/test/ui/ui_test.h b/chrome/test/ui/ui_test.h
index 847fb20..f7f9257 100644
--- a/chrome/test/ui/ui_test.h
+++ b/chrome/test/ui/ui_test.h
@@ -330,6 +330,8 @@ class UITest : public testing::Test {
   static int timeout_ms_;               // Timeout in milliseconds to wait
                                         // for an test to finish.
   ::scoped_ptr<AutomationProxy> server_;
+
+  MessageLoop message_loop_;            // Enables PostTask to main thread.
 };
 
 // These exist only to support the gTest assertion macros, and
diff --git a/chrome/test/ui/ui_test_suite.h b/chrome/test/ui/ui_test_suite.h
index c60eedb..d15db81 100644
--- a/chrome/test/ui/ui_test_suite.h
+++ b/chrome/test/ui/ui_test_suite.h
@@ -18,28 +18,29 @@ class UITestSuite : public ChromeTestSuite {
   virtual void Initialize() {
     ChromeTestSuite::Initialize();
 
+    CommandLine parsed_command_line;
     UITest::set_in_process_renderer(
-        parsed_command_line_.HasSwitch(switches::kSingleProcess));
+        parsed_command_line.HasSwitch(switches::kSingleProcess));
     UITest::set_in_process_plugins(
-        parsed_command_line_.HasSwitch(switches::kInProcessPlugins));
+        parsed_command_line.HasSwitch(switches::kInProcessPlugins));
     UITest::set_no_sandbox(
-        parsed_command_line_.HasSwitch(switches::kNoSandbox));
+        parsed_command_line.HasSwitch(switches::kNoSandbox));
     UITest::set_full_memory_dump(
-        parsed_command_line_.HasSwitch(switches::kFullMemoryCrashReport));
+        parsed_command_line.HasSwitch(switches::kFullMemoryCrashReport));
     UITest::set_safe_plugins(
-        parsed_command_line_.HasSwitch(switches::kSafePlugins));
+        parsed_command_line.HasSwitch(switches::kSafePlugins));
     UITest::set_use_existing_browser(
-        parsed_command_line_.HasSwitch(UITestSuite::kUseExistingBrowser));
+        parsed_command_line.HasSwitch(UITestSuite::kUseExistingBrowser));
     UITest::set_dump_histograms_on_exit(
-        parsed_command_line_.HasSwitch(switches::kDumpHistogramsOnExit));
+        parsed_command_line.HasSwitch(switches::kDumpHistogramsOnExit));
     UITest::set_enable_dcheck(
-        parsed_command_line_.HasSwitch(switches::kEnableDCHECK));
+        parsed_command_line.HasSwitch(switches::kEnableDCHECK));
     UITest::set_silent_dump_on_dcheck(
-        parsed_command_line_.HasSwitch(switches::kSilentDumpOnDCHECK));
+        parsed_command_line.HasSwitch(switches::kSilentDumpOnDCHECK));
     UITest::set_disable_breakpad(
-        parsed_command_line_.HasSwitch(switches::kDisableBreakpad));
+        parsed_command_line.HasSwitch(switches::kDisableBreakpad));
     std::wstring test_timeout =
-        parsed_command_line_.GetSwitchValue(UITestSuite::kTestTimeout);
+        parsed_command_line.GetSwitchValue(UITestSuite::kTestTimeout);
     if (!test_timeout.empty()) {
       UITest::set_test_timeout_ms(_wtoi(test_timeout.c_str()));
     }
diff --git a/chrome/test/ui/view_event_test_base.cc b/chrome/test/ui/view_event_test_base.cc
index edba5dd..a702ea3 100644
--- a/chrome/test/ui/view_event_test_base.cc
+++ b/chrome/test/ui/view_event_test_base.cc
@@ -93,7 +93,7 @@ gfx::Size ViewEventTestBase::GetPreferredSize() {
 
 void ViewEventTestBase::ScheduleMouseMoveInBackground(int x, int y) {
   if (!dnd_thread_.get()) {
-    dnd_thread_.reset(new Thread("mouse-move-thread"));
+    dnd_thread_.reset(new base::Thread("mouse-move-thread"));
     dnd_thread_->Start();
   }
   dnd_thread_->message_loop()->PostDelayedTask(
diff --git a/chrome/test/ui/view_event_test_base.h b/chrome/test/ui/view_event_test_base.h
index b4829b3..e89f734 100644
--- a/chrome/test/ui/view_event_test_base.h
+++ b/chrome/test/ui/view_event_test_base.h
@@ -121,7 +121,7 @@ class ViewEventTestBase : public ChromeViews::WindowDelegate,
   ChromeViews::View* content_view_;
 
   // Thread for posting background MouseMoves.
-  scoped_ptr<Thread> dnd_thread_;
+  scoped_ptr<base::Thread> dnd_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewEventTestBase);
 };
diff --git a/chrome/test/unit/chrome_test_suite.h b/chrome/test/unit/chrome_test_suite.h
index 5f68e77..9432a03 100644
--- a/chrome/test/unit/chrome_test_suite.h
+++ b/chrome/test/unit/chrome_test_suite.h
@@ -20,17 +20,6 @@ public:
   ChromeTestSuite(int argc, char** argv) : TestSuite(argc, argv) {
   }
 
-  virtual ~ChromeTestSuite() {
-    ResourceBundle::CleanupSharedInstance();
-
-    delete g_browser_process;
-    g_browser_process = NULL;
-
-    // Tear down shared StatsTable; prevents unit_tests from leaking it.
-    StatsTable::set_current(NULL);
-    delete stats_table_;
-  }
-
 protected:
 
   virtual void Initialize() {
@@ -44,7 +33,7 @@ protected:
     // NOTE: The user data directory will be erased before each UI test that
     //       uses it, in order to ensure consistency.
     std::wstring user_data_dir =
-        parsed_command_line_.GetSwitchValue(switches::kUserDataDir);
+        CommandLine().GetSwitchValue(switches::kUserDataDir);
     if (user_data_dir.empty() &&
       PathService::Get(base::DIR_EXE, &user_data_dir))
       file_util::AppendToPath(&user_data_dir, L"test_user_data");
@@ -59,6 +48,19 @@ protected:
     StatsTable::set_current(stats_table_);
   }
 
+  virtual void Shutdown() {
+    ResourceBundle::CleanupSharedInstance();
+
+    delete g_browser_process;
+    g_browser_process = NULL;
+
+    // Tear down shared StatsTable; prevents unit_tests from leaking it.
+    StatsTable::set_current(NULL);
+    delete stats_table_;
+    
+    TestSuite::Shutdown();
+  }
+
   StatsTable* stats_table_;
 };
 
diff --git a/chrome/test/unit/run_all_unittests.cc b/chrome/test/unit/run_all_unittests.cc
index 24413d52..8a7419b 100644
--- a/chrome/test/unit/run_all_unittests.cc
+++ b/chrome/test/unit/run_all_unittests.cc
@@ -2,14 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "base/at_exit.h"
 #include "chrome/test/unit/chrome_test_suite.h"
 
 int main(int argc, char **argv) {
-  // Some tests may use base::Singleton<>, thus we need to instanciate
-  // the AtExitManager or else we will leak objects.
-  base::AtExitManager at_exit_manager;  
-
   return ChromeTestSuite(argc, argv).Run();
 }
 
diff --git a/chrome/views/accelerator_handler.h b/chrome/views/accelerator_handler.h
index 093fc847..9405178 100644
--- a/chrome/views/accelerator_handler.h
+++ b/chrome/views/accelerator_handler.h
@@ -15,7 +15,7 @@ namespace ChromeViews {
 // holds a singleton instance of this class which can be used by other
 // custom message loop dispatcher objects to implement default accelerator
 // handling.
-class AcceleratorHandler : public MessageLoop::Dispatcher {
+class AcceleratorHandler : public MessageLoopForUI::Dispatcher {
  public:
    AcceleratorHandler();
   // Dispatcher method. This returns true if an accelerator was
diff --git a/chrome/views/chrome_menu.cc b/chrome/views/chrome_menu.cc
index 6fa61db..a1f9306 100644
--- a/chrome/views/chrome_menu.cc
+++ b/chrome/views/chrome_menu.cc
@@ -1550,14 +1550,14 @@ MenuItemView* MenuController::Run(HWND parent,
   DLOG(INFO) << " entering nested loop, depth=" << nested_depth;
 #endif
 
+  MessageLoopForUI* loop = MessageLoopForUI::current();
   if (MenuItemView::allow_task_nesting_during_run_) {
-    bool did_allow_task_nesting =
-        MessageLoop::current()->NestableTasksAllowed();
-    MessageLoop::current()->SetNestableTasksAllowed(true);
-    MessageLoop::current()->Run(this);
-    MessageLoop::current()->SetNestableTasksAllowed(did_allow_task_nesting);
+    bool did_allow_task_nesting = loop->NestableTasksAllowed();
+    loop->SetNestableTasksAllowed(true);
+    loop->Run(this);
+    loop->SetNestableTasksAllowed(did_allow_task_nesting);
   } else {
-    MessageLoop::current()->Run(this);
+    loop->Run(this);
   }
 
 #ifdef DEBUG_MENU
diff --git a/chrome/views/chrome_menu.h b/chrome/views/chrome_menu.h
index a1ed4ed..1377155 100644
--- a/chrome/views/chrome_menu.h
+++ b/chrome/views/chrome_menu.h
@@ -591,7 +591,7 @@ class SubmenuView : public View {
 // All relevant events are forwarded to the MenuController from SubmenuView
 // and MenuHost.
 
-class MenuController : public MessageLoop::Dispatcher {
+class MenuController : public MessageLoopForUI::Dispatcher {
  public:
   friend class MenuHostRootView;
   friend class MenuItemView;
diff --git a/chrome/views/focus_manager_unittest.cc b/chrome/views/focus_manager_unittest.cc
index c48879d..841f738 100644
--- a/chrome/views/focus_manager_unittest.cc
+++ b/chrome/views/focus_manager_unittest.cc
@@ -217,6 +217,7 @@ class FocusManagerTest : public testing::Test {
   virtual void SetUp();
   virtual void TearDown();
 
+  MessageLoopForUI message_loop_;
   TestViewWindow* test_window_;
 };
 
diff --git a/chrome/views/hwnd_view_container.cc b/chrome/views/hwnd_view_container.cc
index 204ba35..9c723d9 100644
--- a/chrome/views/hwnd_view_container.cc
+++ b/chrome/views/hwnd_view_container.cc
@@ -138,7 +138,7 @@ HWNDViewContainer::HWNDViewContainer()
 }
 
 HWNDViewContainer::~HWNDViewContainer() {
-  MessageLoop::current()->RemoveObserver(this);
+  MessageLoopForUI::current()->RemoveObserver(this);
 }
 
 void HWNDViewContainer::Init(HWND parent,
@@ -183,7 +183,7 @@ void HWNDViewContainer::Init(HWND parent,
   // Sets the RootView as a property, so the automation can introspect windows.
   SetRootViewForHWND(hwnd_, root_view_.get());
 
-  MessageLoop::current()->AddObserver(this);
+  MessageLoopForUI::current()->AddObserver(this);
 
   // Windows special DWM window frame requires a special tooltip manager so
   // that window controls in Chrome windows don't flicker when you move your
diff --git a/chrome/views/hwnd_view_container.h b/chrome/views/hwnd_view_container.h
index 6073b2d..026d6b7 100644
--- a/chrome/views/hwnd_view_container.h
+++ b/chrome/views/hwnd_view_container.h
@@ -75,7 +75,7 @@ class FillLayout : public LayoutManager {
 //
 ///////////////////////////////////////////////////////////////////////////////
 class HWNDViewContainer : public ViewContainer,
-                          public MessageLoop::Observer,
+                          public MessageLoopForUI::Observer,
                           public FocusTraversable,
                           public AcceleratorTarget {
  public:
diff --git a/chrome/views/native_scroll_bar.cc b/chrome/views/native_scroll_bar.cc
index bd81655..00e442c 100644
--- a/chrome/views/native_scroll_bar.cc
+++ b/chrome/views/native_scroll_bar.cc
@@ -190,7 +190,7 @@ class ScrollBarContainer : public CWindowImpl<ScrollBarContainer,
     MSG dummy;
     dummy.hwnd = NULL;
     dummy.message = 0;
-    MessageLoop::current()->DidProcessMessage(dummy);
+    MessageLoopForUI::current()->DidProcessMessage(dummy);
   }
 
   // note: always ignore 2nd param as it is 16 bits
diff --git a/chrome/views/view_unittest.cc b/chrome/views/view_unittest.cc
index 0034104..a658132 100644
--- a/chrome/views/view_unittest.cc
+++ b/chrome/views/view_unittest.cc
@@ -21,6 +21,9 @@ class ViewTest : public testing::Test {
   ~ViewTest() {
     OleUninitialize();
   }
+ 
+ private:
+  MessageLoopForUI message_loop_;
 };
 
 // Paints the RootView.