Fixed how Apps Developer Tools is enabled/disabled

chrome/browser/extensions/install_tracker.cc

Index: chrome/browser/extensions/install_tracker.cc
diff --git a/chrome/browser/extensions/install_tracker.cc b/chrome/browser/extensions/install_tracker.cc
index dc4f3c2484daef6543034860aaee5971b92b51f5..c916d4cdb83f72984f29c5f4c4fb674327272dc2 100644
--- a/chrome/browser/extensions/install_tracker.cc
+++ b/chrome/browser/extensions/install_tracker.cc
@@ -101,9 +101,6 @@ void InstallTracker::Observe(int type,
       const Extension* extension = unload_info->extension;
       FOR_EACH_OBSERVER(InstallObserver, observers_,
                         OnExtensionUnloaded(extension));
-      if (unload_info->reason == extension_misc::UNLOAD_REASON_UNINSTALL)
-        FOR_EACH_OBSERVER(InstallObserver, observers_,
-                          OnExtensionUninstalled(extension));

[asargent_no_longer_on_chrome, 2013/08/30 22:23:00]

I think removing this code block is definitely correct - we should not be
generating additional uninstall events here; instead that should come from the
case in this switch statement matching NOTIFICATION_EXTENSION_UNINSTALLED. 

(ie at a higher level, when something's getting uninstalled they should first
fire a NOTIFICATION_EXTENSION_UNLOADED notification followed by a
NOTIFICATION_EXTENSION_UNINSTALLED one)

       break;
     }
     case chrome::NOTIFICATION_EXTENSION_UNINSTALLED: {