Moved the AppNotification system into extensions namespace

chrome/browser/extensions/app_notify_channel_ui.h

Index: chrome/browser/extensions/app_notify_channel_ui.h
diff --git a/chrome/browser/extensions/app_notify_channel_ui.h b/chrome/browser/extensions/app_notify_channel_ui.h
index 42b76235d49824329754550a0e6f15abb765e992..4192471aaecfb73f5b001c4940ccdf1126e6bbbb 100644
--- a/chrome/browser/extensions/app_notify_channel_ui.h
+++ b/chrome/browser/extensions/app_notify_channel_ui.h
@@ -10,6 +10,8 @@
 class Profile;
 class TabContents;
 
+namespace extensions {
+
 // An interface for prompting a user to sign in to sync so that we can create
 // an app notification channel for one of their apps.
 class AppNotifyChannelUI {
@@ -46,4 +48,6 @@ class AppNotifyChannelUI {
                                     AppNotifyChannelUI::UIType ui_type);
 };
 
+}  // namespace extensions
+
 #endif  // CHROME_BROWSER_EXTENSIONS_APP_NOTIFY_CHANNEL_UI_H_