Add explicit base namespace to string16 users.

chrome/common/chrome_content_client.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_COMMON_CHROME_CONTENT_CLIENT_H_
 #define CHROME_COMMON_CHROME_CONTENT_CLIENT_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 11 matching lines @@
   virtual void SetActiveURL(const GURL& url) OVERRIDE;
   virtual void SetGpuInfo(const gpu::GPUInfo& gpu_info) OVERRIDE;
   virtual void AddPepperPlugins(
       std::vector<content::PepperPluginInfo>* plugins) OVERRIDE;
   virtual void AddAdditionalSchemes(
       std::vector<std::string>* standard_schemes,
       std::vector<std::string>* saveable_shemes) OVERRIDE;
   virtual bool CanHandleWhileSwappedOut(const IPC::Message& msg) OVERRIDE;
   virtual std::string GetProduct() const OVERRIDE;
   virtual std::string GetUserAgent() const OVERRIDE;
-  virtual string16 GetLocalizedString(int message_id) const OVERRIDE;
+  virtual base::string16 GetLocalizedString(int message_id) const OVERRIDE;
   virtual base::StringPiece GetDataResource(
       int resource_id,
       ui::ScaleFactor scale_factor) const OVERRIDE;
   virtual base::RefCountedStaticMemory* GetDataResourceBytes(
       int resource_id) const OVERRIDE;
   virtual gfx::Image& GetNativeImageNamed(int resource_id) const OVERRIDE;
   virtual std::string GetProcessTypeNameInEnglish(int type) OVERRIDE;
 
 #if defined(OS_MACOSX) && !defined(OS_IOS)
   virtual bool GetSandboxProfileForSandboxType(
       int sandbox_type,
       int* sandbox_profile_resource_id) const OVERRIDE;
   virtual std::string GetCarbonInterposePath() const OVERRIDE;
 #endif
 };
 
 #endif  // CHROME_COMMON_CHROME_CONTENT_CLIENT_H_