Move Singleton and related structs to namespace base

extensions/browser/renderer_startup_helper.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 EXTENSIONS_BROWSER_RENDERER_STARTUP_HELPER_H_
 #define EXTENSIONS_BROWSER_RENDERER_STARTUP_HELPER_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/singleton.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
@@ skipping 36 matching lines @@
 // Factory for RendererStartupHelpers. Declared here because this header is
 // rarely included and it's probably cheaper to put it here than to make the
 // compiler generate another object file.
 class RendererStartupHelperFactory : public BrowserContextKeyedServiceFactory {
  public:
   static RendererStartupHelper* GetForBrowserContext(
       content::BrowserContext* context);
   static RendererStartupHelperFactory* GetInstance();
 
  private:
-  friend struct DefaultSingletonTraits<RendererStartupHelperFactory>;
+  friend struct base::DefaultSingletonTraits<RendererStartupHelperFactory>;
 
   RendererStartupHelperFactory();
   ~RendererStartupHelperFactory() override;
 
   // BrowserContextKeyedServiceFactory implementation:
   KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* profile) const override;
   content::BrowserContext* GetBrowserContextToUse(
       content::BrowserContext* context) const override;
   bool ServiceIsCreatedWithBrowserContext() const override;
 
   DISALLOW_COPY_AND_ASSIGN(RendererStartupHelperFactory);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_RENDERER_STARTUP_HELPER_H_