Move UserScript and related into extensions namespace

chrome/browser/extensions/user_script_master.h

Index: chrome/browser/extensions/user_script_master.h
diff --git a/chrome/browser/extensions/user_script_master.h b/chrome/browser/extensions/user_script_master.h
index f41d8fd9f8e0e6c1e5da955f44f278d41b810478..7423b45e14c9107af11f3f92bdb2407c45924d8c 100644
--- a/chrome/browser/extensions/user_script_master.h
+++ b/chrome/browser/extensions/user_script_master.h
@@ -31,6 +31,8 @@ class Profile;
 typedef std::map<std::string, ExtensionSet::ExtensionPathAndDefaultLocale>
     ExtensionsInfo;
 
+namespace extensions {
+
 // Manages a segment of shared memory that contains the user scripts the user
 // has installed.  Lives on the UI thread.
 class UserScriptMaster : public base::RefCountedThreadSafe<UserScriptMaster>,
@@ -167,4 +169,6 @@ class UserScriptMaster : public base::RefCountedThreadSafe<UserScriptMaster>,
   DISALLOW_COPY_AND_ASSIGN(UserScriptMaster);
 };
 
+}  // namespace extensions
+
 #endif  // CHROME_BROWSER_EXTENSIONS_USER_SCRIPT_MASTER_H_