Move Extension into extensions namespace

chrome/browser/ui/gtk/extensions/extension_keybinding_registry_gtk.h

Index: chrome/browser/ui/gtk/extensions/extension_keybinding_registry_gtk.h
diff --git a/chrome/browser/ui/gtk/extensions/extension_keybinding_registry_gtk.h b/chrome/browser/ui/gtk/extensions/extension_keybinding_registry_gtk.h
index 41d0006d41b697ff90aad9fa175d34e544c09e8c..e17977c21174d5997749e75a6baba88e0fcccb56 100644
--- a/chrome/browser/ui/gtk/extensions/extension_keybinding_registry_gtk.h
+++ b/chrome/browser/ui/gtk/extensions/extension_keybinding_registry_gtk.h
@@ -14,9 +14,12 @@
 #include "ui/base/accelerators/accelerator_gtk.h"
 #include "ui/base/gtk/gtk_signal.h"
 
-class Extension;
 class Profile;
 
+namespace extensions {
+class Extension;
+}
+
 typedef struct _GtkAccelGroup GtkAccelGroup;
 typedef struct _GdkEventKey GdkEventKey;
 
@@ -42,8 +45,10 @@ class ExtensionKeybindingRegistryGtk
 
  protected:
   // Overridden from ExtensionKeybindingRegistry:
-  virtual void AddExtensionKeybinding(const Extension* extension) OVERRIDE;
-  virtual void RemoveExtensionKeybinding(const Extension* extension) OVERRIDE;
+  virtual void AddExtensionKeybinding(
+      const extensions::Extension* extension) OVERRIDE;
+  virtual void RemoveExtensionKeybinding(
+      const extensions::Extension* extension) OVERRIDE;
 
  private:
   // The accelerator handler for when the extension command shortcuts are