Add base:: to string16 in extensions/.

extensions/common/manifest_handlers/csp_info.h

 // Copyright 2013 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_COMMON_MANIFEST_HANDLERS_CSP_INFO_H_
 #define EXTENSIONS_COMMON_MANIFEST_HANDLERS_CSP_INFO_H_
 
 #include <string>
 
 #include "extensions/common/extension.h"
@@ skipping 20 matching lines @@
       const Extension* extension,
       const std::string& relative_path);
 };
 
 // Parses "content_security_policy" and "app.content_security_policy" keys.
 class CSPHandler : public ManifestHandler {
  public:
   explicit CSPHandler(bool is_platform_app);
   virtual ~CSPHandler();
 
-  virtual bool Parse(Extension* extension, string16* error) OVERRIDE;
+  virtual bool Parse(Extension* extension, base::string16* error) OVERRIDE;
   virtual bool AlwaysParseForType(Manifest::Type type) const OVERRIDE;
 
  private:
   virtual const std::vector<std::string> Keys() const OVERRIDE;
 
   bool is_platform_app_;
 
   DISALLOW_COPY_AND_ASSIGN(CSPHandler);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_MANIFEST_HANDLERS_CSP_INFO_H_