Move Extension into extensions namespace

chrome/browser/ui/browser_window.h

Index: chrome/browser/ui/browser_window.h
diff --git a/chrome/browser/ui/browser_window.h b/chrome/browser/ui/browser_window.h
index a64196c8fc529ddcda1cc586ea14b25b367e944d..70dc2a1a0df35f09bc525db5b6665a6e7f07a87e 100644
--- a/chrome/browser/ui/browser_window.h
+++ b/chrome/browser/ui/browser_window.h
@@ -34,12 +34,15 @@ class WebContents;
 struct SSLStatus;
 }
 
+namespace extensions {
+class Extension;
+}
+
 namespace gfx {
 class Rect;
 class Size;
 }
 
-class Extension;
 
 enum DevToolsDockSide {
   DEVTOOLS_DOCK_SIDE_BOTTOM = 0,
@@ -290,7 +293,8 @@ class BrowserWindow : public BaseWindow {
 
   // Shows the create chrome app shortcut dialog box.
   virtual void ShowCreateChromeAppShortcutsDialog(Profile* profile,
-                                                  const Extension* app) = 0;
+      const extensions::Extension* app) = 0;
+
 
   // Clipboard commands applied to the whole browser window.
   virtual void Cut() = 0;