Makes Launcher remove itself as an observer from any windows it's

ui/aura_shell/launcher/launcher.cc

Index: ui/aura_shell/launcher/launcher.cc
diff --git a/ui/aura_shell/launcher/launcher.cc b/ui/aura_shell/launcher/launcher.cc
index 4792c8d4a935b6fd0a757bc5d8b8765775d83c51..845965605c252379a6b667b586cc266232d39038 100644
--- a/ui/aura_shell/launcher/launcher.cc
+++ b/ui/aura_shell/launcher/launcher.cc
@@ -43,6 +43,10 @@ Launcher::Launcher(aura::ToplevelWindowContainer* window_container)
 
 Launcher::~Launcher() {
   window_container_->RemoveObserver(this);
+  for (WindowMap::iterator i = known_windows_.begin();
+       i != known_windows_.end(); ++i) {
+    i->first->RemoveObserver(this);
+  }
 }
 
 void Launcher::MaybeAdd(aura::Window* window) {