Add a unified observer to replace NetworkManagerObserver

chrome/browser/chromeos/net/connectivity_state_helper.h

Index: chrome/browser/chromeos/net/connectivity_state_helper.h
diff --git a/chrome/browser/chromeos/net/connectivity_state_helper.h b/chrome/browser/chromeos/net/connectivity_state_helper.h
index 030b5c691e44a7be017b7e5386a3039224fe96cf..70da1148766a744e670b2c0b077bbf39d35d1502 100644
--- a/chrome/browser/chromeos/net/connectivity_state_helper.h
+++ b/chrome/browser/chromeos/net/connectivity_state_helper.h
@@ -5,9 +5,10 @@
 #ifndef CHROME_BROWSER_CHROMEOS_NET_CONNECTIVITY_STATE_HELPER_H_
 #define CHROME_BROWSER_CHROMEOS_NET_CONNECTIVITY_STATE_HELPER_H_
 
+#include "base/observer_list.h"
 #include "chrome/browser/chromeos/cros/network_library.h"
+#include "chrome/browser/chromeos/net/connectivity_state_helper_observer.h"
 #include "chromeos/network/network_state_handler.h"
-#include "chromeos/network/network_state_handler_observer.h"
 
 namespace chromeos {
 
@@ -49,8 +50,15 @@ class ConnectivityStateHelper {
   // Returns true if we have a default network and are in online state.
   virtual bool DefaultNetworkOnline() = 0;
 
+  // Add/remove observers for listening to connection manager changes.
+  virtual void AddNetworkManagerObserver(
+      ConnectivityStateHelperObserver* observer);
+  virtual void RemoveNetworkManagerObserver(
+      ConnectivityStateHelperObserver* observer);

[stevenjb, 2013/03/11 23:11:05]

I wonder if this would be better as just "Add/RemoveObserver"? I think that
everywhere we use this the calling code is just observing "Connectivity" and
doesn't know or care about the concept of a "Manager"

[gauravsh, 2013/03/12 00:30:25]

I did this to keep things simple and match current behavior - NetworkLibrary
defines at least 3 different types of observers - NetworkManagerObserver,
NetworkObserver and DeviceObserver, and how they are used is fairly inconsistent
throughout the code base. Once I add support for these other *Observers in
NetworkLibrary, I will also their Add*Observer equivalents.

Again, all this distinction will go away once everything is using the
NetworkStateHandlerObserver by default.

[stevenjb, 2013/03/12 15:53:34]

I guess the question is whether or not it makes sense to preserve this class
after we eliminate NetworkLibrary? Having a "ConnectivityStateHelper" that just
tracks connectivity state makes a fair bit of sense to me and could simplify the
calling code. Let's discuss in person what we really want to do here.

+
  protected:
   ConnectivityStateHelper() {}
+  ObserverList<ConnectivityStateHelperObserver> network_manager_observers_;
 };
 
 }  // namespace chromeos