Add SystemTrayObservers

chrome/browser/chromeos/locale_change_guard.cc

Index: chrome/browser/chromeos/locale_change_guard.cc
diff --git a/chrome/browser/chromeos/locale_change_guard.cc b/chrome/browser/chromeos/locale_change_guard.cc
index 606bfb49cbadf3529bf5580c1df43d2b9d43a4ef..7c573af03093d3ca0764a12ee40387b462c24395 100644
--- a/chrome/browser/chromeos/locale_change_guard.cc
+++ b/chrome/browser/chromeos/locale_change_guard.cc
@@ -6,6 +6,8 @@
 
 #include "ash/shell.h"
 #include "ash/system/tray/system_tray.h"
+#include "ash/system/tray/system_tray_delegate.h"
+#include "ash/system/tray/system_tray_observers.h"
 #include "base/bind.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
@@ -171,9 +173,13 @@ void LocaleChangeGuard::Check() {
     PrepareChangingLocale(from_locale, to_locale);
   }
 
-  if (ash::Shell::GetInstance()->status_area_widget()) {
-    ash::Shell::GetInstance()->system_tray()->locale_observer()->
-        OnLocaleChanged(this, cur_locale, from_locale_, to_locale_);
+  ash::SystemTrayObservers* observers =
+      ash::Shell::GetInstance()->tray_delegate()->GetSystemTrayObservers();

[oshima, 2012/11/09 19:21:50]

TrayDelegate has NotifyXXX methods for several other 
notifications, so it may make sense to define such methods
for these notifications as well. Yon you don't have to expose
observers and eliminate NULL check.

[sadrul, 2012/11/09 23:26:32]

I agree that it would be nice if these places all didn't have to loop over the
observer-list.

There could be TrayDelegate::NotifyXXX. Another approach would be to create a
Shell::SystemTrayProxy (or SystemTrayObserver), which is notified of these
changes. The Proxy/Observer can then iterate over the system-trays and update
their observers accordingly.

[stevenjb, 2012/11/09 23:40:45]

Yeah, I started to create NotifyXXX, but realized that most of these
could/should be moved to Ash at some point and removed from the
SystemTrayDelegate entirely.

That said, I'm OK with moving these to NotifyXXX in the meanwhile, and moving
all of NotifyXXX to SystemTrayObservers such that all of the calls look like:

ash::Shell::GetInstance()->tray_delegate()->GetSystemTrayObservers()->NotifyXXX(...)

A bit of a mouthful, but it would tidy up SystemTrayDelegate a bit. Sound
reasonable?

We could also put GetSystemTrayObservers() directly into Shell to make this less
verbose?

+  if (observers) {
+    FOR_EACH_OBSERVER(
+        ash::LocaleObserver,
+        observers->locale_observers(),
+        OnLocaleChanged(this, cur_locale, from_locale_, to_locale_));
   }
 }