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

ui/aura_shell/launcher/launcher.cc

 // Copyright (c) 2011 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.
 
 #include "ui/aura_shell/launcher/launcher.h"
 
 #include "ui/aura/toplevel_window_container.h"
 #include "ui/aura_shell/launcher/launcher_model.h"
 #include "ui/aura_shell/launcher/launcher_view.h"
 #include "ui/aura_shell/shell.h"
@@ skipping 25 matching lines @@
   widget_->Init(params);
   gfx::Size pref = static_cast<views::View*>(launcher_view)->GetPreferredSize();
   widget_->SetBounds(gfx::Rect(0, 0, pref.width(), pref.height()));
   widget_->SetContentsView(launcher_view);
   widget_->Show();
   widget_->GetNativeView()->set_name("LauncherView");
 }
 
 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) {
   if (known_windows_[window] == true)
     return;  // We already tried to add this window.
 
   known_windows_[window] = true;
   ShellDelegate* delegate = Shell::GetInstance()->delegate();
   if (!delegate)
     return;
@@ skipping 29 matching lines @@
     model_->RemoveItemAt(i - model_->items().begin());
 }
 
 void Launcher::OnWindowVisibilityChanged(aura::Window* window,
                                          bool visibile) {
   if (visibile && !known_windows_[window])
     MaybeAdd(window);
 }
 
 }  // namespace aura_shell