Add base:: to string16 in extensions/.

extensions/common/manifest_handlers/shared_module_info.h

Index: extensions/common/manifest_handlers/shared_module_info.h
diff --git a/extensions/common/manifest_handlers/shared_module_info.h b/extensions/common/manifest_handlers/shared_module_info.h
index db51594b07e2088eca85eb7075b6fcfaa747e5fa..4240ed7a81778e24e7e31718627d691158facb91 100644
--- a/extensions/common/manifest_handlers/shared_module_info.h
+++ b/extensions/common/manifest_handlers/shared_module_info.h
@@ -19,7 +19,7 @@ class SharedModuleInfo : public Extension::ManifestData {
   SharedModuleInfo();
   virtual ~SharedModuleInfo();
 
-  bool Parse(const Extension* extension, string16* error);
+  bool Parse(const Extension* extension, base::string16* error);
 
   struct ImportInfo {
     std::string extension_id;
@@ -57,7 +57,7 @@ class SharedModuleHandler : public ManifestHandler {
   SharedModuleHandler();
   virtual ~SharedModuleHandler();
 
-  virtual bool Parse(Extension* extension, string16* error) OVERRIDE;
+  virtual bool Parse(Extension* extension, base::string16* error) OVERRIDE;
   virtual bool Validate(const Extension* extension,
                         std::string* error,
                         std::vector<InstallWarning>* warnings) const OVERRIDE;