Move Extension into extensions namespace

chrome/browser/extensions/theme_installed_infobar_delegate.h

Index: chrome/browser/extensions/theme_installed_infobar_delegate.h
diff --git a/chrome/browser/extensions/theme_installed_infobar_delegate.h b/chrome/browser/extensions/theme_installed_infobar_delegate.h
index 28cad72d0c46e3440fb40e34ad9d8e25315457e3..3e7b0d18b5cb4a07441e7b402f726707e758748d 100644
--- a/chrome/browser/extensions/theme_installed_infobar_delegate.h
+++ b/chrome/browser/extensions/theme_installed_infobar_delegate.h
@@ -13,10 +13,13 @@
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
-class Extension;
 class ExtensionService;
 class ThemeService;
 
+namespace extensions {
+class Extension;
+}
+
 // When a user installs a theme, we display it immediately, but provide an
 // infobar allowing them to cancel.
 class ThemeInstalledInfoBarDelegate : public ConfirmInfoBarDelegate,
@@ -25,13 +28,13 @@ class ThemeInstalledInfoBarDelegate : public ConfirmInfoBarDelegate,
   ThemeInstalledInfoBarDelegate(InfoBarTabHelper* infobar_helper,
                                 ExtensionService* extension_service,
                                 ThemeService* theme_service,
-                                const Extension* new_theme,
+                                const extensions::Extension* new_theme,
                                 const std::string& previous_theme_id,
                                 bool previous_using_native_theme);
 
   // Returns true if the given theme is the same as the one associated with this
   // info bar.
-  bool MatchesTheme(const Extension* theme) const;
+  bool MatchesTheme(const extensions::Extension* theme) const;
 
  protected:
   virtual ~ThemeInstalledInfoBarDelegate();