Revert "Change event routers from singletons to being owned by the ExtensionService."

This breaks, among other things, multi-profile and the first run dialog.
Reverting at least for M13.

This reverts commit 45758c29485736d7164085e6b7f8bf0999df1c4f.

BUG=81745
TEST=none

Review URL: http://codereview.chromium.org/7084006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@87083 0039d316-1c4b-4281-b951-d872f2087c98

25 files changed, 229 insertions, 192 deletions

diff --git a/chrome/browser/chromeos/extensions/file_browser_event_router.cc b/chrome/browser/chromeos/extensions/file_browser_event_router.cc
index 51f5b6a..723cdc6 100644
--- a/chrome/browser/chromeos/extensions/file_browser_event_router.cc
+++ b/chrome/browser/chromeos/extensions/file_browser_event_router.cc
@@ -47,24 +47,18 @@ DictionaryValue* DiskToDictionaryValue(
   return result;
 }
 
-ExtensionFileBrowserEventRouter::ExtensionFileBrowserEventRouter(
-    Profile* profile)
-    : profile_(profile) {
-  DCHECK(profile);
+ExtensionFileBrowserEventRouter::ExtensionFileBrowserEventRouter()
+    : profile_(NULL) {
 }
 
 ExtensionFileBrowserEventRouter::~ExtensionFileBrowserEventRouter() {
-  if (!profile_)
-    return;
-  if (!chromeos::CrosLibrary::Get()->EnsureLoaded())
-    return;
-  chromeos::MountLibrary* lib =
-      chromeos::CrosLibrary::Get()->GetMountLibrary();
-  lib->RemoveObserver(this);
-  profile_ = NULL;
 }
 
-void ExtensionFileBrowserEventRouter::ObserveFileSystemEvents() {
+void ExtensionFileBrowserEventRouter::ObserveFileSystemEvents(
+    Profile* profile) {
+  if (!profile)
+    return;
+  profile_ = profile;
   if (!chromeos::CrosLibrary::Get()->EnsureLoaded())
     return;
   if (chromeos::UserManager::Get()->user_is_logged_in()) {
@@ -76,6 +70,23 @@ void ExtensionFileBrowserEventRouter::ObserveFileSystemEvents() {
   }
 }
 
+void ExtensionFileBrowserEventRouter::StopObservingFileSystemEvents() {
+  if (!profile_)
+    return;
+  if (!chromeos::CrosLibrary::Get()->EnsureLoaded())
+    return;
+  chromeos::MountLibrary* lib =
+      chromeos::CrosLibrary::Get()->GetMountLibrary();
+  lib->RemoveObserver(this);
+  profile_ = NULL;
+}
+
+// static
+ExtensionFileBrowserEventRouter*
+    ExtensionFileBrowserEventRouter::GetInstance() {
+  return Singleton<ExtensionFileBrowserEventRouter>::get();
+}
+
 void ExtensionFileBrowserEventRouter::DiskChanged(
     chromeos::MountLibraryEventType event,
     const chromeos::MountLibrary::Disk* disk) {
diff --git a/chrome/browser/chromeos/extensions/file_browser_event_router.h b/chrome/browser/chromeos/extensions/file_browser_event_router.h
index 9b58656..320a80d 100644
--- a/chrome/browser/chromeos/extensions/file_browser_event_router.h
+++ b/chrome/browser/chromeos/extensions/file_browser_event_router.h
@@ -24,12 +24,12 @@ class SystemNotification;
 class ExtensionFileBrowserEventRouter
     : public chromeos::MountLibrary::Observer {
  public:
-  explicit ExtensionFileBrowserEventRouter(Profile* profile);
-  virtual ~ExtensionFileBrowserEventRouter();
+  static ExtensionFileBrowserEventRouter* GetInstance();
 
-  // Starts observing file system change events. Currently only
+  // Starts/stops observing file system change events. Currently only
   // MountLibrary events are being observed.
-  void ObserveFileSystemEvents();
+  void ObserveFileSystemEvents(Profile* profile);
+  void StopObservingFileSystemEvents();
 
   // MountLibrary::Observer overrides.
   virtual void DiskChanged(chromeos::MountLibraryEventType event,
@@ -38,10 +38,14 @@ class ExtensionFileBrowserEventRouter
                              const std::string& device_path);
 
  private:
+  friend struct DefaultSingletonTraits<ExtensionFileBrowserEventRouter>;
   typedef std::map<std::string, linked_ptr<chromeos::SystemNotification> >
       NotificationMap;
   typedef std::map<std::string, std::string> MountPointMap;
 
+  ExtensionFileBrowserEventRouter();
+  virtual ~ExtensionFileBrowserEventRouter();
+
   // USB mount event handlers.
   void OnDiskAdded(const chromeos::MountLibrary::Disk* disk);
   void OnDiskRemoved(const chromeos::MountLibrary::Disk* disk);
diff --git a/chrome/browser/chromeos/login/wizard_accessibility_helper.cc b/chrome/browser/chromeos/login/wizard_accessibility_helper.cc
index e8dd4cf..6d152fa 100644
--- a/chrome/browser/chromeos/login/wizard_accessibility_helper.cc
+++ b/chrome/browser/chromeos/login/wizard_accessibility_helper.cc
@@ -8,7 +8,6 @@
 #include "base/stl_util-inl.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/extension_accessibility_api.h"
-#include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
@@ -115,7 +114,7 @@ void WizardAccessibilityHelper::SetAccessibilityEnabled(bool enabled) {
     prefService->SetBoolean(prefs::kAccessibilityEnabled, enabled);
     prefService->ScheduleSavePersistentPrefs();
   }
-  profile_->GetExtensionService()->accessibility_event_router()->
+  ExtensionAccessibilityEventRouter::GetInstance()->
       SetAccessibilityEnabled(enabled);
   if (doSpeak) {
     accessibility_handler_->Speak(enabled ?
diff --git a/chrome/browser/extensions/extension_accessibility_api.cc b/chrome/browser/extensions/extension_accessibility_api.cc
index 8b8042a..cc694d1 100644
--- a/chrome/browser/extensions/extension_accessibility_api.cc
+++ b/chrome/browser/extensions/extension_accessibility_api.cc
@@ -34,16 +34,20 @@ std::string ControlInfoToJsonString(const AccessibilityControlInfo* info) {
   return json_args;
 }
 
-ExtensionAccessibilityEventRouter::ExtensionAccessibilityEventRouter()
-    : enabled_(false) {
+ExtensionAccessibilityEventRouter*
+    ExtensionAccessibilityEventRouter::GetInstance() {
+  return Singleton<ExtensionAccessibilityEventRouter>::get();
 }
 
+ExtensionAccessibilityEventRouter::ExtensionAccessibilityEventRouter()
+    : enabled_(false) {}
+
 ExtensionAccessibilityEventRouter::~ExtensionAccessibilityEventRouter() {
   STLDeleteElements(&on_enabled_listeners_);
   STLDeleteElements(&on_disabled_listeners_);
 }
 
-void ExtensionAccessibilityEventRouter::Init() {
+void ExtensionAccessibilityEventRouter::ObserveProfile(Profile* profile) {
   last_focused_control_dict_.Clear();
 
   if (registrar_.IsEmpty()) {
@@ -188,9 +192,8 @@ void ExtensionAccessibilityEventRouter::DispatchEvent(
 bool SetAccessibilityEnabledFunction::RunImpl() {
   bool enabled;
   EXTENSION_FUNCTION_VALIDATE(args_->GetBoolean(0, &enabled));
-  ExtensionAccessibilityEventRouter* accessibility_event_router =
-      profile()->GetExtensionService()->accessibility_event_router();
-  accessibility_event_router->SetAccessibilityEnabled(enabled);
+  ExtensionAccessibilityEventRouter::GetInstance()
+      ->SetAccessibilityEnabled(enabled);
   return true;
 }
 
@@ -198,8 +201,8 @@ bool GetFocusedControlFunction::RunImpl() {
   // Get the serialized dict from the last focused control and return it.
   // However, if the dict is empty, that means we haven't seen any focus
   // events yet, so return null instead.
-  ExtensionAccessibilityEventRouter* accessibility_event_router =
-      profile()->GetExtensionService()->accessibility_event_router();
+  ExtensionAccessibilityEventRouter *accessibility_event_router =
+      ExtensionAccessibilityEventRouter::GetInstance();
   DictionaryValue *last_focused_control_dict =
       accessibility_event_router->last_focused_control_dict();
   if (last_focused_control_dict->size()) {
diff --git a/chrome/browser/extensions/extension_accessibility_api.h b/chrome/browser/extensions/extension_accessibility_api.h
index 93eac1ff..2dfc4c1 100644
--- a/chrome/browser/extensions/extension_accessibility_api.h
+++ b/chrome/browser/extensions/extension_accessibility_api.h
@@ -10,6 +10,7 @@
 #include <vector>
 
 #include "base/callback_old.h"
+#include "base/memory/singleton.h"
 #include "base/values.h"
 #include "chrome/browser/accessibility_events.h"
 #include "chrome/browser/extensions/extension_function.h"
@@ -20,10 +21,11 @@
 // to the extension system.
 class ExtensionAccessibilityEventRouter : public NotificationObserver {
  public:
-  explicit ExtensionAccessibilityEventRouter();
-  virtual ~ExtensionAccessibilityEventRouter();
+  // Single instance of the event router.
+  static ExtensionAccessibilityEventRouter* GetInstance();
 
-  void Init();
+  // Safe to call multiple times.
+  void ObserveProfile(Profile* profile);
 
   // Get the dict representing the last control that received an
   // OnControlFocus event.
@@ -43,6 +45,11 @@ class ExtensionAccessibilityEventRouter : public NotificationObserver {
   void AddOnDisabledListener(Callback* callback);
 
  private:
+  friend struct DefaultSingletonTraits<ExtensionAccessibilityEventRouter>;
+
+  ExtensionAccessibilityEventRouter();
+  virtual ~ExtensionAccessibilityEventRouter();
+
   // NotificationObserver::Observe.
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
diff --git a/chrome/browser/extensions/extension_bookmarks_module.cc b/chrome/browser/extensions/extension_bookmarks_module.cc
index 1358ee6..3e3a769 100644
--- a/chrome/browser/extensions/extension_bookmarks_module.cc
+++ b/chrome/browser/extensions/extension_bookmarks_module.cc
@@ -118,13 +118,22 @@ void BookmarksFunction::Observe(NotificationType type,
   Release();  // Balanced in Run().
 }
 
-ExtensionBookmarkEventRouter::ExtensionBookmarkEventRouter() {}
+// static
+ExtensionBookmarkEventRouter* ExtensionBookmarkEventRouter::GetInstance() {
+  return Singleton<ExtensionBookmarkEventRouter>::get();
+}
+
+ExtensionBookmarkEventRouter::ExtensionBookmarkEventRouter() {
+}
 
-ExtensionBookmarkEventRouter::~ExtensionBookmarkEventRouter() {}
+ExtensionBookmarkEventRouter::~ExtensionBookmarkEventRouter() {
+}
 
 void ExtensionBookmarkEventRouter::Observe(BookmarkModel* model) {
-  model->AddObserver(this);
-  model_ = model;
+  if (models_.find(model) == models_.end()) {
+    model->AddObserver(this);
+    models_.insert(model);
+  }
 }
 
 void ExtensionBookmarkEventRouter::DispatchEvent(Profile *profile,
diff --git a/chrome/browser/extensions/extension_bookmarks_module.h b/chrome/browser/extensions/extension_bookmarks_module.h
index eff5c92..1b8efed 100644
--- a/chrome/browser/extensions/extension_bookmarks_module.h
+++ b/chrome/browser/extensions/extension_bookmarks_module.h
@@ -12,6 +12,7 @@
 
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/singleton.h"
 #include "chrome/browser/bookmarks/bookmark_model_observer.h"
 #include "chrome/browser/extensions/extension_function.h"
 #include "chrome/browser/ui/shell_dialogs.h"
@@ -24,10 +25,11 @@ class FilePath;
 // the extension system.
 class ExtensionBookmarkEventRouter : public BookmarkModelObserver {
  public:
-  explicit ExtensionBookmarkEventRouter();
+  static ExtensionBookmarkEventRouter* GetInstance();
   virtual ~ExtensionBookmarkEventRouter();
 
-  // Initialize to observe this bookmark model.
+  // Call this for each model to observe.  Safe to call multiple times per
+  // model.
   void Observe(BookmarkModel* model);
 
   // BookmarkModelObserver:
@@ -55,13 +57,18 @@ class ExtensionBookmarkEventRouter : public BookmarkModelObserver {
   virtual void BookmarkImportEnding(BookmarkModel* model) OVERRIDE;
 
  private:
+  ExtensionBookmarkEventRouter();
+  friend struct DefaultSingletonTraits<ExtensionBookmarkEventRouter>;
+
   // Helper to actually dispatch an event to extension listeners.
   void DispatchEvent(Profile* profile,
                      const char* event_name,
                      const std::string& json_args);
 
-  // The model being observed.
-  BookmarkModel* model_;
+  // These are stored so that Observe can be called multiple times safely.
+  // This way the caller doesn't have to know whether it's already observing
+  // a particular model or not.  The pointers are not owned by this object.
+  std::set<BookmarkModel*> models_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionBookmarkEventRouter);
 };
diff --git a/chrome/browser/extensions/extension_cookies_api.cc b/chrome/browser/extensions/extension_cookies_api.cc
index d5eabaa..83c535d 100644
--- a/chrome/browser/extensions/extension_cookies_api.cc
+++ b/chrome/browser/extensions/extension_cookies_api.cc
@@ -25,9 +25,10 @@
 
 namespace keys = extension_cookies_api_constants;
 
-ExtensionCookiesEventRouter::ExtensionCookiesEventRouter() {}
-
-ExtensionCookiesEventRouter::~ExtensionCookiesEventRouter() {}
+// static
+ExtensionCookiesEventRouter* ExtensionCookiesEventRouter::GetInstance() {
+  return Singleton<ExtensionCookiesEventRouter>::get();
+}
 
 void ExtensionCookiesEventRouter::Init() {
   if (registrar_.IsEmpty()) {
diff --git a/chrome/browser/extensions/extension_cookies_api.h b/chrome/browser/extensions/extension_cookies_api.h
index 276c336..286c8ba 100644
--- a/chrome/browser/extensions/extension_cookies_api.h
+++ b/chrome/browser/extensions/extension_cookies_api.h
@@ -12,6 +12,7 @@
 #include <string>
 
 #include "base/memory/ref_counted.h"
+#include "base/memory/singleton.h"
 #include "base/time.h"
 #include "chrome/browser/extensions/extension_function.h"
 #include "chrome/browser/net/chrome_cookie_notification_details.h"
@@ -30,12 +31,17 @@ class URLRequestContextGetter;
 // extension system.
 class ExtensionCookiesEventRouter : public NotificationObserver {
  public:
-  explicit ExtensionCookiesEventRouter();
-  virtual ~ExtensionCookiesEventRouter();
+  // Single instance of the event router.
+  static ExtensionCookiesEventRouter* GetInstance();
 
   void Init();
 
  private:
+  friend struct DefaultSingletonTraits<ExtensionCookiesEventRouter>;
+
+  ExtensionCookiesEventRouter() {}
+  virtual ~ExtensionCookiesEventRouter() {}
+
   // NotificationObserver implementation.
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
diff --git a/chrome/browser/extensions/extension_event_router.cc b/chrome/browser/extensions/extension_event_router.cc
index 76a419c..a86bf1c 100644
--- a/chrome/browser/extensions/extension_event_router.cc
+++ b/chrome/browser/extensions/extension_event_router.cc
@@ -106,7 +106,7 @@ void ExtensionEventRouter::AddEventListener(
   // We lazily tell the TaskManager to start updating when listeners to the
   // processes.onUpdated event arrive.
   if (event_name.compare(extension_processes_api_constants::kOnUpdated) == 0)
-    profile_->GetExtensionService()->processes_event_router()->ListenerAdded();
+    ExtensionProcessesEventRouter::GetInstance()->ListenerAdded();
 }
 
 void ExtensionEventRouter::RemoveEventListener(
@@ -127,8 +127,7 @@ void ExtensionEventRouter::RemoveEventListener(
   // If a processes.onUpdated event listener is removed (or a process with one
   // exits), then we let the TaskManager know that it has one fewer listener.
   if (event_name.compare(extension_processes_api_constants::kOnUpdated) == 0)
-    profile_->GetExtensionService()->processes_event_router()->
-        ListenerRemoved();
+    ExtensionProcessesEventRouter::GetInstance()->ListenerRemoved();
 
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
diff --git a/chrome/browser/extensions/extension_history_api.cc b/chrome/browser/extensions/extension_history_api.cc
index 3287184..9ead422 100644
--- a/chrome/browser/extensions/extension_history_api.cc
+++ b/chrome/browser/extensions/extension_history_api.cc
@@ -64,39 +64,49 @@ void AddVisitNode(const history::VisitRow& row, ListValue* list) {
 
 }  // namespace
 
-ExtensionHistoryEventRouter::ExtensionHistoryEventRouter(Profile* profile)
-    : profile_(profile) {}
+ExtensionHistoryEventRouter* ExtensionHistoryEventRouter::GetInstance() {
+  return Singleton<ExtensionHistoryEventRouter>::get();
+}
 
-ExtensionHistoryEventRouter::~ExtensionHistoryEventRouter() {}
+void ExtensionHistoryEventRouter::ObserveProfile(Profile* profile) {
+  NotificationSource source = Source<Profile>(profile);
+  if (profiles_.find(source.map_key()) == profiles_.end())
+    profiles_[source.map_key()] = profile;
 
-void ExtensionHistoryEventRouter::Init() {
-  NotificationSource source = Source<Profile>(profile_);
   if (registrar_.IsEmpty()) {
     registrar_.Add(this,
                    NotificationType::HISTORY_URL_VISITED,
-                   source);
+                   NotificationService::AllSources());
     registrar_.Add(this,
                    NotificationType::HISTORY_URLS_DELETED,
-                   source);
+                   NotificationService::AllSources());
   }
 }
 
+ExtensionHistoryEventRouter::ExtensionHistoryEventRouter() {}
+
+ExtensionHistoryEventRouter::~ExtensionHistoryEventRouter() {}
+
 void ExtensionHistoryEventRouter::Observe(NotificationType type,
                                           const NotificationSource& source,
                                           const NotificationDetails& details) {
-  switch (type.value) {
-    case NotificationType::HISTORY_URL_VISITED:
-      HistoryUrlVisited(
-          profile_,
-          Details<const history::URLVisitedDetails>(details).ptr());
-      break;
-    case NotificationType::HISTORY_URLS_DELETED:
-      HistoryUrlsRemoved(
-          profile_,
-          Details<const history::URLsDeletedDetails>(details).ptr());
-      break;
-    default:
-      NOTREACHED();
+  ProfileMap::iterator it = profiles_.find(source.map_key());
+  if (it != profiles_.end()) {
+    Profile* profile = it->second;
+    switch (type.value) {
+      case NotificationType::HISTORY_URL_VISITED:
+        HistoryUrlVisited(
+            profile,
+            Details<const history::URLVisitedDetails>(details).ptr());
+        break;
+      case NotificationType::HISTORY_URLS_DELETED:
+        HistoryUrlsRemoved(
+            profile,
+            Details<const history::URLsDeletedDetails>(details).ptr());
+        break;
+      default:
+        NOTREACHED();
+    }
   }
 }
 
diff --git a/chrome/browser/extensions/extension_history_api.h b/chrome/browser/extensions/extension_history_api.h
index b5f7208..f6ddcdc 100644
--- a/chrome/browser/extensions/extension_history_api.h
+++ b/chrome/browser/extensions/extension_history_api.h
@@ -9,23 +9,28 @@
 #include <map>
 #include <string>
 
+#include "base/memory/singleton.h"
 #include "chrome/browser/extensions/extension_function.h"
 #include "chrome/browser/history/history.h"
 #include "chrome/browser/history/history_notifications.h"
 #include "content/common/notification_registrar.h"
 
-class Profile;
-
 // Observes History service and routes the notifications as events to the
 // extension system.
 class ExtensionHistoryEventRouter : public NotificationObserver {
  public:
-  explicit ExtensionHistoryEventRouter(Profile* profile);
-  virtual ~ExtensionHistoryEventRouter();
+  // Single instance of the event router.
+  static ExtensionHistoryEventRouter* GetInstance();
 
-  void Init();
+  // Safe to call multiple times.
+  void ObserveProfile(Profile* profile);
 
  private:
+  friend struct DefaultSingletonTraits<ExtensionHistoryEventRouter>;
+
+  ExtensionHistoryEventRouter();
+  virtual ~ExtensionHistoryEventRouter();
+
   // NotificationObserver::Observe.
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
@@ -44,8 +49,9 @@ class ExtensionHistoryEventRouter : public NotificationObserver {
   // Used for tracking registrations to history service notifications.
   NotificationRegistrar registrar_;
 
-  // The associated Profile owns us transitively via ExtensionService.
-  Profile* profile_;
+  // Registered profiles.
+  typedef std::map<uintptr_t, Profile*> ProfileMap;
+  ProfileMap profiles_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionHistoryEventRouter);
 };
diff --git a/chrome/browser/extensions/extension_management_api.cc b/chrome/browser/extensions/extension_management_api.cc
index 73b905b..0053b1d 100644
--- a/chrome/browser/extensions/extension_management_api.cc
+++ b/chrome/browser/extensions/extension_management_api.cc
@@ -248,6 +248,11 @@ bool UninstallFunction::RunImpl() {
   return true;
 }
 
+// static
+ExtensionManagementEventRouter* ExtensionManagementEventRouter::GetInstance() {
+  return Singleton<ExtensionManagementEventRouter>::get();
+}
+
 ExtensionManagementEventRouter::ExtensionManagementEventRouter() {}
 
 ExtensionManagementEventRouter::~ExtensionManagementEventRouter() {}
diff --git a/chrome/browser/extensions/extension_management_api.h b/chrome/browser/extensions/extension_management_api.h
index 68aae0b..04b2c8c 100644
--- a/chrome/browser/extensions/extension_management_api.h
+++ b/chrome/browser/extensions/extension_management_api.h
@@ -6,6 +6,7 @@
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_MANAGEMENT_API_H__
 #pragma once
 
+#include "base/memory/singleton.h"
 #include "chrome/browser/extensions/extension_function.h"
 #include "content/common/notification_observer.h"
 #include "content/common/notification_registrar.h"
@@ -49,12 +50,18 @@ class UninstallFunction : public ExtensionManagementFunction {
 
 class ExtensionManagementEventRouter : public NotificationObserver {
  public:
-  explicit ExtensionManagementEventRouter();
-  virtual ~ExtensionManagementEventRouter();
+  // Get the singleton instance of the event router.
+  static ExtensionManagementEventRouter* GetInstance();
 
+  // Performs one-time initialization of our singleton.
   void Init();
 
  private:
+  friend struct DefaultSingletonTraits<ExtensionManagementEventRouter>;
+
+  ExtensionManagementEventRouter();
+  virtual ~ExtensionManagementEventRouter();
+
   // NotificationObserver implementation.
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
diff --git a/chrome/browser/extensions/extension_preference_api.cc b/chrome/browser/extensions/extension_preference_api.cc
index b297905..ae65a58 100644
--- a/chrome/browser/extensions/extension_preference_api.cc
+++ b/chrome/browser/extensions/extension_preference_api.cc
@@ -222,11 +222,6 @@ class PrefMapping {
 
 ExtensionPreferenceEventRouter::ExtensionPreferenceEventRouter(
     Profile* profile) : profile_(profile) {
-}
-
-ExtensionPreferenceEventRouter::~ExtensionPreferenceEventRouter() {}
-
-void ExtensionPreferenceEventRouter::Init() {
   registrar_.Init(profile_->GetPrefs());
   incognito_registrar_.Init(profile_->GetOffTheRecordPrefs());
   for (size_t i = 0; i < arraysize(kPrefMapping); ++i) {
@@ -235,6 +230,8 @@ void ExtensionPreferenceEventRouter::Init() {
   }
 }
 
+ExtensionPreferenceEventRouter::~ExtensionPreferenceEventRouter() { }
+
 void ExtensionPreferenceEventRouter::Observe(
     NotificationType type,
     const NotificationSource& source,
diff --git a/chrome/browser/extensions/extension_preference_api.h b/chrome/browser/extensions/extension_preference_api.h
index 6f6b3da..06897ce 100644
--- a/chrome/browser/extensions/extension_preference_api.h
+++ b/chrome/browser/extensions/extension_preference_api.h
@@ -17,8 +17,6 @@ class ExtensionPreferenceEventRouter : public NotificationObserver {
   explicit ExtensionPreferenceEventRouter(Profile* profile);
   virtual ~ExtensionPreferenceEventRouter();
 
-  void Init();
-
  private:
   // NotificationObserver implementation.
   virtual void Observe(NotificationType type,
diff --git a/chrome/browser/extensions/extension_processes_api.cc b/chrome/browser/extensions/extension_processes_api.cc
index 92d61b8..266afdc 100644
--- a/chrome/browser/extensions/extension_processes_api.cc
+++ b/chrome/browser/extensions/extension_processes_api.cc
@@ -42,17 +42,21 @@ DictionaryValue* CreateProcessValue(int process_id,
   return result;
 }
 
-ExtensionProcessesEventRouter::ExtensionProcessesEventRouter(Profile* profile)
-    : profile_(profile) {
+ExtensionProcessesEventRouter* ExtensionProcessesEventRouter::GetInstance() {
+  return Singleton<ExtensionProcessesEventRouter>::get();
+}
+
+ExtensionProcessesEventRouter::ExtensionProcessesEventRouter() {
+  model_ = TaskManager::GetInstance()->model();
+  model_->AddObserver(this);
 }
 
 ExtensionProcessesEventRouter::~ExtensionProcessesEventRouter() {
   model_->RemoveObserver(this);
 }
 
-void ExtensionProcessesEventRouter::Init() {
-  model_ = TaskManager::GetInstance()->model();
-  model_->AddObserver(this);
+void ExtensionProcessesEventRouter::ObserveProfile(Profile* profile) {
+  profiles_.insert(profile);
 }
 
 void ExtensionProcessesEventRouter::ListenerAdded() {
@@ -134,8 +138,12 @@ void ExtensionProcessesEventRouter::OnItemsChanged(int start, int length) {
     std::string json_args;
     base::JSONWriter::Write(&args, false, &json_args);
 
-    // Notify the profile.
-    DispatchEvent(profile_, keys::kOnUpdated, json_args);
+    // Notify each profile that is interested.
+    for (ProfileSet::iterator it = profiles_.begin();
+         it != profiles_.end(); it++) {
+      Profile* profile = *it;
+      DispatchEvent(profile, keys::kOnUpdated, json_args);
+    }
   }
 }
 
diff --git a/chrome/browser/extensions/extension_processes_api.h b/chrome/browser/extensions/extension_processes_api.h
index 18e871f..fe0a2f9 100644
--- a/chrome/browser/extensions/extension_processes_api.h
+++ b/chrome/browser/extensions/extension_processes_api.h
@@ -13,16 +13,15 @@
 #include "chrome/browser/task_manager/task_manager.h"
 #include "content/common/notification_registrar.h"
 
-class Profile;
-
 // Observes the Task Manager and routes the notifications as events to the
 // extension system.
 class ExtensionProcessesEventRouter : public TaskManagerModelObserver {
  public:
-  explicit ExtensionProcessesEventRouter(Profile* profile);
-  virtual ~ExtensionProcessesEventRouter();
+  // Single instance of the event router.
+  static ExtensionProcessesEventRouter* GetInstance();
 
-  void Init();
+  // Safe to call multiple times.
+  void ObserveProfile(Profile* profile);
 
   // Called when an extension process wants to listen to process events.
   void ListenerAdded();
@@ -31,6 +30,10 @@ class ExtensionProcessesEventRouter : public TaskManagerModelObserver {
   void ListenerRemoved();
 
  private:
+  friend struct DefaultSingletonTraits<ExtensionProcessesEventRouter>;
+
+  ExtensionProcessesEventRouter();
+  virtual ~ExtensionProcessesEventRouter();
 
   // TaskManagerModelObserver methods.
   virtual void OnModelChanged() {}
@@ -45,8 +48,9 @@ class ExtensionProcessesEventRouter : public TaskManagerModelObserver {
   // Used for tracking registrations to process related notifications.
   NotificationRegistrar registrar_;
 
-  // The associated Profile owns us transitively via ExtensionService.
-  Profile* profile_;
+  // Registered profiles.
+  typedef std::set<Profile*> ProfileSet;
+  ProfileSet profiles_;
 
   // TaskManager to observe for updates.
   TaskManagerModel* model_;
diff --git a/chrome/browser/extensions/extension_service.cc b/chrome/browser/extensions/extension_service.cc
index ecf60b1..a409420 100644
--- a/chrome/browser/extensions/extension_service.cc
+++ b/chrome/browser/extensions/extension_service.cc
@@ -537,35 +537,34 @@ ExtensionService::~ExtensionService() {
     ExternalExtensionProviderInterface* provider = i->get();
     provider->ServiceShutdown();
   }
+
+#if defined(OS_CHROMEOS)
+  if (event_routers_initialized_) {
+    ExtensionFileBrowserEventRouter::GetInstance()->
+        StopObservingFileSystemEvents();
+  }
+#endif
 }
 
 void ExtensionService::InitEventRouters() {
   if (event_routers_initialized_)
     return;
 
-  history_event_router_.reset(new ExtensionHistoryEventRouter(profile_));
-  history_event_router_->Init();
-  accessibility_event_router_.reset(new ExtensionAccessibilityEventRouter());
-  accessibility_event_router_->Init();
+  ExtensionHistoryEventRouter::GetInstance()->ObserveProfile(profile_);
+  ExtensionAccessibilityEventRouter::GetInstance()->ObserveProfile(profile_);
   browser_event_router_.reset(new ExtensionBrowserEventRouter(profile_));
   browser_event_router_->Init();
   preference_event_router_.reset(new ExtensionPreferenceEventRouter(profile_));
-  preference_event_router_->Init();
-  bookmark_event_router_.reset(new ExtensionBookmarkEventRouter());
-  bookmark_event_router_->Observe(profile_->GetBookmarkModel());
-  cookies_event_router_.reset(new ExtensionCookiesEventRouter());
-  cookies_event_router_->Init();
-  management_event_router_.reset(new ExtensionManagementEventRouter());
-  management_event_router_->Init();
-  processes_event_router_.reset(new ExtensionProcessesEventRouter(profile_));
-  processes_event_router_->Init();
-  web_navigation_event_router_.reset(new ExtensionWebNavigationEventRouter());
-  web_navigation_event_router_->Init();
+  ExtensionBookmarkEventRouter::GetInstance()->Observe(
+      profile_->GetBookmarkModel());
+  ExtensionCookiesEventRouter::GetInstance()->Init();
+  ExtensionManagementEventRouter::GetInstance()->Init();
+  ExtensionProcessesEventRouter::GetInstance()->ObserveProfile(profile_);
+  ExtensionWebNavigationEventRouter::GetInstance()->Init();
 
 #if defined(OS_CHROMEOS)
-  file_browser_event_router_.reset(
-      new ExtensionFileBrowserEventRouter(profile_));
-  file_browser_event_router_->ObserveFileSystemEvents();
+  ExtensionFileBrowserEventRouter::GetInstance()->ObserveFileSystemEvents(
+      profile_);
   ExtensionMediaPlayerEventRouter::GetInstance()->Init(profile_);
 #endif
 
diff --git a/chrome/browser/extensions/extension_service.h b/chrome/browser/extensions/extension_service.h
index bdc78ca..1771e4e 100644
--- a/chrome/browser/extensions/extension_service.h
+++ b/chrome/browser/extensions/extension_service.h
@@ -39,18 +39,10 @@
 #include "content/common/property_bag.h"
 
 class CrxInstaller;
-class ExtensionAccessibilityEventRouter;
-class ExtensionBookmarkEventRouter;
 class ExtensionBrowserEventRouter;
 class ExtensionContentSettingsStore;
-class ExtensionCookiesEventRouter;
-class ExtensionFileBrowserEventRouter;
-class ExtensionHistoryEventRouter;
 class ExtensionInstallUI;
-class ExtensionManagementEventRouter;
 class ExtensionPreferenceEventRouter;
-class ExtensionProcessesEventRouter;
-class ExtensionWebNavigationEventRouter;
 class ExtensionServiceBackend;
 struct ExtensionSyncData;
 class ExtensionToolbarModel;
@@ -442,18 +434,10 @@ class ExtensionService
 
   ExtensionMenuManager* menu_manager() { return &menu_manager_; }
 
-  ExtensionAccessibilityEventRouter* accessibility_event_router() {
-    return accessibility_event_router_.get();
-  }
-
   ExtensionBrowserEventRouter* browser_event_router() {
     return browser_event_router_.get();
   }
 
-  ExtensionProcessesEventRouter* processes_event_router() {
-    return processes_event_router_.get();
-  }
-
   // Notify the frontend that there was an error loading an extension.
   // This method is public because ExtensionServiceBackend can post to here.
   void ReportExtensionLoadError(const FilePath& extension_path,
@@ -695,19 +679,9 @@ class ExtensionService
   // Flag to make sure event routers are only initialized once.
   bool event_routers_initialized_;
 
-  scoped_ptr<ExtensionHistoryEventRouter> history_event_router_;
-  scoped_ptr<ExtensionAccessibilityEventRouter> accessibility_event_router_;
   scoped_ptr<ExtensionBrowserEventRouter> browser_event_router_;
+
   scoped_ptr<ExtensionPreferenceEventRouter> preference_event_router_;
-  scoped_ptr<ExtensionBookmarkEventRouter> bookmark_event_router_;
-  scoped_ptr<ExtensionCookiesEventRouter> cookies_event_router_;
-  scoped_ptr<ExtensionManagementEventRouter> management_event_router_;
-  scoped_ptr<ExtensionProcessesEventRouter> processes_event_router_;
-  scoped_ptr<ExtensionWebNavigationEventRouter> web_navigation_event_router_;
-
-#if defined(OS_CHROMEOS)
-  scoped_ptr<ExtensionFileBrowserEventRouter> file_browser_event_router_;
-#endif
 
   // A collection of external extension providers.  Each provider reads
   // a source of external extension information.  Examples include the
diff --git a/chrome/browser/extensions/extension_webnavigation_api.cc b/chrome/browser/extensions/extension_webnavigation_api.cc
index 14d6318..04da675 100644
--- a/chrome/browser/extensions/extension_webnavigation_api.cc
+++ b/chrome/browser/extensions/extension_webnavigation_api.cc
@@ -251,6 +251,12 @@ ExtensionWebNavigationEventRouter::ExtensionWebNavigationEventRouter() {}
 
 ExtensionWebNavigationEventRouter::~ExtensionWebNavigationEventRouter() {}
 
+// static
+ExtensionWebNavigationEventRouter*
+ExtensionWebNavigationEventRouter::GetInstance() {
+  return Singleton<ExtensionWebNavigationEventRouter>::get();
+}
+
 void ExtensionWebNavigationEventRouter::Init() {
   if (registrar_.IsEmpty()) {
     registrar_.Add(this,
diff --git a/chrome/browser/extensions/extension_webnavigation_api.h b/chrome/browser/extensions/extension_webnavigation_api.h
index 63938a5..9f475dc 100644
--- a/chrome/browser/extensions/extension_webnavigation_api.h
+++ b/chrome/browser/extensions/extension_webnavigation_api.h
@@ -12,6 +12,7 @@
 
 #include <map>
 
+#include "base/memory/singleton.h"
 #include "chrome/browser/extensions/extension_function.h"
 #include "content/browser/tab_contents/tab_contents_observer.h"
 #include "content/common/notification_observer.h"
@@ -131,12 +132,19 @@ class ExtensionWebNavigationTabObserver : public TabContentsObserver {
 // system.
 class ExtensionWebNavigationEventRouter : public NotificationObserver {
  public:
-  explicit ExtensionWebNavigationEventRouter();
-  virtual ~ExtensionWebNavigationEventRouter();
+  // Returns the singleton instance of the event router.
+  static ExtensionWebNavigationEventRouter* GetInstance();
 
+  // Invoked by the extensions service once the extension system is fully set
+  // up and can start dispatching events to extensions.
   void Init();
 
  private:
+  friend struct DefaultSingletonTraits<ExtensionWebNavigationEventRouter>;
+
+  ExtensionWebNavigationEventRouter();
+  virtual ~ExtensionWebNavigationEventRouter();
+
   // NotificationObserver implementation.
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
diff --git a/chrome/browser/ui/views/accessibility_event_router_views.cc b/chrome/browser/ui/views/accessibility_event_router_views.cc
index 58aa6aa..34fb85e 100644
--- a/chrome/browser/ui/views/accessibility_event_router_views.cc
+++ b/chrome/browser/ui/views/accessibility_event_router_views.cc
@@ -10,7 +10,6 @@
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/extension_accessibility_api.h"
-#include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/views/location_bar/location_bar_view.h"
@@ -35,9 +34,7 @@ using views::FocusManager;
 
 AccessibilityEventRouterViews::AccessibilityEventRouterViews()
     : most_recent_profile_(NULL),
-      ALLOW_THIS_IN_INITIALIZER_LIST(method_factory_(this)),
-      accessibility_enabled_overridden_for_testing_(false),
-      accessibility_enabled_override_value_(false) {
+      ALLOW_THIS_IN_INITIALIZER_LIST(method_factory_(this)) {
 }
 
 AccessibilityEventRouterViews::~AccessibilityEventRouterViews() {
@@ -50,6 +47,11 @@ AccessibilityEventRouterViews* AccessibilityEventRouterViews::GetInstance() {
 
 void AccessibilityEventRouterViews::HandleAccessibilityEvent(
     views::View* view, ui::AccessibilityTypes::Event event_type) {
+  if (!ExtensionAccessibilityEventRouter::GetInstance()->
+      IsAccessibilityEnabled()) {
+    return;
+  }
+
   switch (event_type) {
     case ui::AccessibilityTypes::EVENT_FOCUS:
       DispatchAccessibilityNotification(
@@ -90,12 +92,13 @@ void AccessibilityEventRouterViews::HandleMenuItemFocused(
     int item_index,
     int item_count,
     bool has_submenu) {
-  if (!most_recent_profile_)
+  if (!ExtensionAccessibilityEventRouter::GetInstance()->
+      IsAccessibilityEnabled()) {
     return;
+  }
 
-  if (!IsAccessibilityEnabled(most_recent_profile_)) {
+  if (!most_recent_profile_)
     return;
-  }
 
   AccessibilityMenuItemInfo info(
       most_recent_profile_,
@@ -111,15 +114,6 @@ void AccessibilityEventRouterViews::HandleMenuItemFocused(
 // Private methods
 //
 
-bool AccessibilityEventRouterViews::IsAccessibilityEnabled(Profile* profile) {
-  if (accessibility_enabled_overridden_for_testing_) {
-    return accessibility_enabled_override_value_;
-  }
-  DCHECK(profile);
-  return profile->GetExtensionService()->accessibility_event_router()->
-      IsAccessibilityEnabled();
-}
-
 std::string AccessibilityEventRouterViews::GetViewName(views::View* view) {
   ui::AccessibleViewState state;
   view->GetAccessibleState(&state);
@@ -147,10 +141,6 @@ void AccessibilityEventRouterViews::DispatchAccessibilityNotification(
     return;
   }
 
-  if (!IsAccessibilityEnabled(profile)) {
-    return;
-  }
-
   most_recent_profile_ = profile;
   std::string class_name = view->GetClassName();
 
@@ -305,8 +295,3 @@ void AccessibilityEventRouterViews::SendCheckboxNotification(
   SendAccessibilityNotification(type, &info);
 }
 
-void AccessibilityEventRouterViews::SetAccessibilityEnabledForTesting(
-    bool enabled) {
-  accessibility_enabled_overridden_for_testing_ = true;
-  accessibility_enabled_override_value_ = enabled;
-}
diff --git a/chrome/browser/ui/views/accessibility_event_router_views.h b/chrome/browser/ui/views/accessibility_event_router_views.h
index 7039a8b..44908bd 100644
--- a/chrome/browser/ui/views/accessibility_event_router_views.h
+++ b/chrome/browser/ui/views/accessibility_event_router_views.h
@@ -73,8 +73,6 @@ class AccessibilityEventRouterViews {
   FRIEND_TEST_ALL_PREFIXES(AccessibilityEventRouterViewsTest,
                            TestFocusNotification);
 
-  bool IsAccessibilityEnabled(Profile* profile);
-
   // Checks the type of the view and calls one of the more specific
   // Send*Notification methods, below.
   void DispatchAccessibilityNotification(
@@ -113,11 +111,6 @@ class AccessibilityEventRouterViews {
   void RecursiveGetMenuItemIndexAndCount(
       views::View* menu, views::View* item, int* index, int* count);
 
-  // Used for testing only. Overrides the accessibility enabled setting
-  // so the test doesn't depend directly on the ExtensionService and
-  // ExtensionAccessibilityEventRouter.
-  void SetAccessibilityEnabledForTesting(bool enabled);
-
   // The profile associated with the most recent window event  - used to
   // figure out where to route a few events that can't be directly traced
   // to a window with a profile (like menu events).
@@ -126,10 +119,6 @@ class AccessibilityEventRouterViews {
   // Used to defer handling of some events until the next time
   // through the event loop.
   ScopedRunnableMethodFactory<AccessibilityEventRouterViews> method_factory_;
-
-  // Used for testing only, with SetAccessibilityEnabledForTesting.
-  bool accessibility_enabled_overridden_for_testing_;
-  bool accessibility_enabled_override_value_;
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_ACCESSIBILITY_EVENT_ROUTER_VIEWS_H_
diff --git a/chrome/browser/ui/views/accessibility_event_router_views_unittest.cc b/chrome/browser/ui/views/accessibility_event_router_views_unittest.cc
index 3dee35fb..3ca6466 100644
--- a/chrome/browser/ui/views/accessibility_event_router_views_unittest.cc
+++ b/chrome/browser/ui/views/accessibility_event_router_views_unittest.cc
@@ -8,8 +8,6 @@
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/extensions/extension_accessibility_api.h"
-#include "chrome/browser/extensions/extension_service.h"
-#include "chrome/browser/extensions/test_extension_service.h"
 #include "chrome/browser/ui/views/accessibility_event_router_views.h"
 #include "chrome/test/testing_profile.h"
 #include "content/common/notification_registrar.h"
@@ -149,15 +147,6 @@ TEST_F(AccessibilityEventRouterViewsTest, TestFocusNotification) {
   // Put the view in a window.
   views::Window* window = CreateWindowWithContents(contents);
 
-  // Create a profile and associate it with this window.
-  TestingProfile profile;
-  window->AsWidget()->native_widget()->SetNativeWindowProperty(
-      Profile::kProfileKey, &profile);
-
-  // To begin with, accessibility event notifications are off.
-  AccessibilityEventRouterViews::GetInstance()->
-      SetAccessibilityEnabledForTesting(false);
-
   // Set focus to the first button initially.
   button1->RequestFocus();
 
@@ -168,8 +157,14 @@ TEST_F(AccessibilityEventRouterViewsTest, TestFocusNotification) {
                 NotificationService::AllSources());
 
   // Switch on accessibility event notifications.
-  AccessibilityEventRouterViews::GetInstance()->
-      SetAccessibilityEnabledForTesting(true);
+  ExtensionAccessibilityEventRouter* accessibility_event_router =
+      ExtensionAccessibilityEventRouter::GetInstance();
+  accessibility_event_router->SetAccessibilityEnabled(true);
+
+  // Create a profile and associate it with this window.
+  TestingProfile profile;
+  window->AsWidget()->native_widget()->SetNativeWindowProperty(
+      Profile::kProfileKey, &profile);
 
   // Change the accessible name of button3.
   button3->SetAccessibleName(ASCIIToUTF16(kButton3NewASCII));