WIP: Eliminate event.target() usage from TrayEventFilter

ash/container_delegate_aura.cc

Index: ash/container_delegate_aura.cc
diff --git a/ash/container_delegate_aura.cc b/ash/container_delegate_aura.cc
new file mode 100644
index 0000000000000000000000000000000000000000..976a3338ea59eee3f88c7c9d8d8780e8e35bfa64
--- /dev/null
+++ b/ash/container_delegate_aura.cc
@@ -0,0 +1,37 @@
+// Copyright 2016 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/container_delegate_aura.h"
+
+#include "ash/root_window_controller.h"
+#include "ash/shell_window_ids.h"
+#include "ui/views/widget/widget.h"
+
+namespace ash {
+namespace {
+
+bool IsInContainer(views::Widget* widget, int container_id) {
+  aura::Window* window = widget->GetNativeWindow();
+  RootWindowController* root_controller =
+      GetRootWindowController(window->GetRootWindow());
+  if (!root_controller)
+    return false;
+  return root_controller->GetContainer(container_id)->Contains(window);
+}
+
+}  // namespace
+
+ContainerDelegateAura::ContainerDelegateAura() {}
+
+ContainerDelegateAura::~ContainerDelegateAura() {}
+
+bool ContainerDelegateAura::IsInMenuContainer(views::Widget* widget) {
+  return IsInContainer(widget, kShellWindowId_MenuContainer);
+}
+
+bool ContainerDelegateAura::IsInStatusContainer(views::Widget* widget) {
+  return IsInContainer(widget, kShellWindowId_StatusContainer);
+}
+
+}  // namespace ash