Move Extension into extensions namespace

chrome/common/extensions/extension_permission_set.h

Index: chrome/common/extensions/extension_permission_set.h
diff --git a/chrome/common/extensions/extension_permission_set.h b/chrome/common/extensions/extension_permission_set.h
index 954c0ca39331ef2a5b8ce0de92912a8beeca90be..405460f5bdf0c0031ffd4a3ab3f2651b716e7ab1 100644
--- a/chrome/common/extensions/extension_permission_set.h
+++ b/chrome/common/extensions/extension_permission_set.h
@@ -20,9 +20,12 @@
 
 // TODO(jstritar): Move each class to its own file in extensions/permissions.
 
-class Extension;
 class ExtensionPermissionsInfo;
 
+namespace extensions {
+class Extension;
+}
+
 // When prompting the user to install or approve permissions, we display
 // messages describing the effects of the permissions rather than listing the
 // permissions themselves. Each ExtensionPermissionMessage represents one of the
@@ -291,7 +294,7 @@ class ExtensionPermissionSet
   // the api and host permissions (|apis| and |hosts|). The effective hosts
   // of the newly created permission set will be inferred from the |extension|
   // manifest, |apis| and |hosts|.
-  ExtensionPermissionSet(const Extension* extension,
+  ExtensionPermissionSet(const extensions::Extension* extension,
                          const ExtensionAPIPermissionSet& apis,
                          const URLPatternSet& explicit_hosts,
                          const ExtensionOAuth2Scopes& scopes);
@@ -412,7 +415,7 @@ class ExtensionPermissionSet
       bool exclude_file_scheme);
 
   // Initializes the set based on |extension|'s manifest data.
-  void InitImplicitExtensionPermissions(const Extension* extension);
+  void InitImplicitExtensionPermissions(const extensions::Extension* extension);
 
   // Initializes the effective host permission based on the data in this set.
   void InitEffectiveHosts();