Move Extension into extensions namespace

chrome/browser/app_controller_mac.mm

Index: chrome/browser/app_controller_mac.mm
diff --git a/chrome/browser/app_controller_mac.mm b/chrome/browser/app_controller_mac.mm
index 5d676e5252dd60f10426ec996aacda52280c130b..9c5efcd8c15b1581ae1d2ee16d5a895cc6220ff3 100644
--- a/chrome/browser/app_controller_mac.mm
+++ b/chrome/browser/app_controller_mac.mm
@@ -926,7 +926,7 @@ const AEEventClass kAECloudPrintUninstallClass = 'GCPu';
   BackgroundApplicationListModel applications(profile);
   DCHECK(tag >= 0 &&
          tag < static_cast<int>(applications.size()));
-  const Extension* extension = applications.GetExtension(tag);
+  const extensions::Extension* extension = applications.GetExtension(tag);
   BackgroundModeManager::LaunchBackgroundApplication(profile, extension);
 }
 
@@ -1240,7 +1240,8 @@ const AEEventClass kAECloudPrintUninstallClass = 'GCPu';
       NSString* menuStr =
           l10n_util::GetNSStringWithFixup(IDS_BACKGROUND_APPS_MAC);
       scoped_nsobject<NSMenu> appMenu([[NSMenu alloc] initWithTitle:menuStr]);
-      for (ExtensionList::const_iterator cursor = applications.begin();
+      for (extensions::ExtensionList::const_iterator cursor =
+            applications.begin();
            cursor != applications.end();
            ++cursor, ++position) {
         DCHECK_EQ(applications.GetPosition(*cursor), position);