Add FilePath to base namespace.

chrome/browser/extensions/app_notification_storage.h

Index: chrome/browser/extensions/app_notification_storage.h
diff --git a/chrome/browser/extensions/app_notification_storage.h b/chrome/browser/extensions/app_notification_storage.h
index 1daf6b2d8a5cdb20314403fcdc6a70460517bd3a..5fda2fd44b0f067b0fd3c0390a8ee5a61ac1c697 100644
--- a/chrome/browser/extensions/app_notification_storage.h
+++ b/chrome/browser/extensions/app_notification_storage.h
@@ -9,7 +9,9 @@
 
 #include "chrome/browser/extensions/app_notification.h"
 
+namespace base {
 class FilePath;
+}
 
 namespace extensions {
 
@@ -20,7 +22,7 @@ namespace extensions {
 class AppNotificationStorage {
  public:
   // Must be called on the FILE thread. The storage will be created at |path|.
-  static AppNotificationStorage* Create(const FilePath& path);
+  static AppNotificationStorage* Create(const base::FilePath& path);
 
   virtual ~AppNotificationStorage();