Move ObserverList to base namespace.

chrome/browser/extensions/api/chrome_extensions_api_client.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_API_CHROME_EXTENSIONS_API_CLIENT_H_
 #define CHROME_BROWSER_EXTENSIONS_API_CHROME_EXTENSIONS_API_CLIENT_H_
 
 #include "base/compiler_specific.h"
 #include "extensions/browser/api/extensions_api_client.h"
 
 namespace extensions {
 
 // Extra support for extensions APIs in Chrome.
 class ChromeExtensionsAPIClient : public ExtensionsAPIClient {
  public:
   ChromeExtensionsAPIClient();
   ~ChromeExtensionsAPIClient() override;
 
   // ExtensionsApiClient implementation.
   void AddAdditionalValueStoreCaches(
       content::BrowserContext* context,
       const scoped_refptr<SettingsStorageFactory>& factory,
-      const scoped_refptr<ObserverListThreadSafe<SettingsObserver>>& observers,
+      const scoped_refptr<base::ObserverListThreadSafe<SettingsObserver>>&
+          observers,
       std::map<settings_namespace::Namespace, ValueStoreCache*>* caches)
       override;
   AppViewGuestDelegate* CreateAppViewGuestDelegate() const override;
   ExtensionOptionsGuestDelegate* CreateExtensionOptionsGuestDelegate(
       ExtensionOptionsGuest* guest) const override;
   ExtensionViewGuestDelegate* CreateExtensionViewGuestDelegate(
       ExtensionViewGuest* guest) const override;
   scoped_ptr<MimeHandlerViewGuestDelegate> CreateMimeHandlerViewGuestDelegate(
       MimeHandlerViewGuest* guest) const override;
   WebViewGuestDelegate* CreateWebViewGuestDelegate(
@@ skipping 11 matching lines @@
       const override;
   ManagementAPIDelegate* CreateManagementAPIDelegate() const override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ChromeExtensionsAPIClient);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_CHROME_EXTENSIONS_API_CLIENT_H_