DesktopAura: Track windows "owned" via the DesktopWindowTreeHost

chrome/test/base/view_event_test_platform_part_mac.cc

+// Copyright 2017 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 "chrome/test/base/view_event_test_platform_part.h"
+
+namespace {
+
+// ViewEventTestPlatformPart implementation for Views, but non-Aura.
+class ViewEventTestPlatformPartDefault : public ViewEventTestPlatformPart {
+ public:
+  ViewEventTestPlatformPartDefault() {}
+  ~ViewEventTestPlatformPartDefault() override {}
+
+  // ViewEventTestPlatformPart:
+  gfx::NativeWindow GetContext() override { return nullptr; }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ViewEventTestPlatformPartDefault);
+};
+
+}  // namespace
+
+// static
+ViewEventTestPlatformPart* ViewEventTestPlatformPart::Create(
+    ui::ContextFactory* context_factory,
+    ui::ContextFactoryPrivate* context_factory_private) {
+  return new ViewEventTestPlatformPartDefault();
+}