RootWindowController::GetFullscreenWindow() should return the active one.

ash/root_window_controller.cc

 // Copyright (c) 2012 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 "ash/root_window_controller.h"
 
 #include <queue>
 #include <vector>
 
 #include "ash/ash_constants.h"
@@ skipping 483 matching lines @@
     return;
   }
 
   Shell::GetInstance()->UpdateShelfVisibility();
 }
 
 void RootWindowController::UpdateShelfVisibility() {
   shelf_->shelf_layout_manager()->UpdateVisibilityState();
 }
 
-const aura::Window* RootWindowController::GetFullscreenWindow() const {
-  const aura::Window* container = GetContainer(kShellWindowId_DefaultContainer);
-  for (size_t i = 0; i < container->children().size(); ++i) {
-    aura::Window* child = container->children()[i];
-    if (wm::IsWindowFullscreen(child))
-      return child;
+const aura::Window* RootWindowController::GetTopmostFullscreenWindow() const {
+  const aura::Window::Windows& windows =
+      GetContainer(kShellWindowId_DefaultContainer)->children();
+  for (aura::Window::Windows::const_reverse_iterator iter = windows.rbegin();
+       iter != windows.rend(); ++iter) {
+    if (wm::IsWindowFullscreen(*iter))
+      return *iter;
   }
   return NULL;
 }
 
 void RootWindowController::InitKeyboard() {
   if (keyboard::IsKeyboardEnabled()) {
     aura::Window* parent = root_window();
 
     keyboard::KeyboardControllerProxy* proxy =
         Shell::GetInstance()->delegate()->CreateKeyboardControllerProxy();
@@ skipping 288 matching lines @@
 
 void RootWindowController::OnTouchHudProjectionToggled(bool enabled) {
   if (enabled)
     EnableTouchHudProjection();
   else
     DisableTouchHudProjection();
 }
 
 }  // namespace internal
 }  // namespace ash