Add skeleton implementation of ExtensionPushMessagingEventRouter.

chrome/browser/extensions/api/push_messaging/invalidation_handler_observer.h

Index: chrome/browser/extensions/api/push_messaging/invalidation_handler_observer.h
diff --git a/chrome/browser/extensions/api/push_messaging/invalidation_handler_observer.h b/chrome/browser/extensions/api/push_messaging/invalidation_handler_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..74082339d7eeecf5f631f27d4965b18bece93a4e
--- /dev/null
+++ b/chrome/browser/extensions/api/push_messaging/invalidation_handler_observer.h
@@ -0,0 +1,22 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_EXTENSIONS_API_PUSH_MESSAGING_INVALIDATION_HANDLER_OBSERVER_H_

[Munjal (Google), 2012/07/31 17:36:12]

I think Pete is using api/push/ folder in another patch. Can you sync up with
him about the folder?

[dcheng, 2012/07/31 19:04:11]

He's OOO this week. However, I talked to Mark about this and since we're
planning on calling it "push messaging", I made it consistent throughout the
code, documentation and file paths.

[Munjal (Google), 2012/07/31 23:09:58]

Okay, SG.

+#define CHROME_BROWSER_EXTENSIONS_API_PUSH_MESSAGING_INVALIDATION_HANDLER_OBSERVER_H_
+
+#include <string>
+
+namespace extensions {
+
+class InvalidationHandlerObserver {

[Munjal (Google), 2012/07/31 17:36:12]

It will be nice to have a description for this class.

[dcheng, 2012/07/31 19:04:11]

Done.

+ public:
+  virtual ~InvalidationHandlerObserver() {}
+  virtual void OnMessage(const std::string& extension_id,
+                         int subchannel,

[Munjal (Google), 2012/07/31 17:36:12]

Nit: sub_channel?

[dcheng, 2012/07/31 19:04:11]

I ended up picking subchannel since "subchannel" is a more popular term than
"sub channel", in both Google search (from what I could tell) and code search.

+                         const std::string& payload) = 0;
+};

[Munjal (Google), 2012/07/31 17:36:12]

Nit: I am not sure if we need DISALLOW_COPY_AND_ASSIGN for abstract classes. May
be it is good to add it?

[dcheng, 2012/07/31 19:04:11]

I took a look at several other pure virtual classes, and none of them used
DISALLOW_COPY_AND_ASSIGN (content::NotificationObserver,
syncer::SyncNotifierObserver, several in base/)

+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_PUSH_MESSAGING_INVALIDATION_HANDLER_OBSERVER_H_