Creates mus test helper class

components/mus/public/cpp/tests/window_tree_client_impl_private.cc

Index: components/mus/public/cpp/tests/window_tree_client_impl_private.cc
diff --git a/components/mus/public/cpp/tests/window_tree_client_impl_private.cc b/components/mus/public/cpp/tests/window_tree_client_impl_private.cc
new file mode 100644
index 0000000000000000000000000000000000000000..795e3dc0d2020322c46105298d64e2af29c53425
--- /dev/null
+++ b/components/mus/public/cpp/tests/window_tree_client_impl_private.cc
@@ -0,0 +1,36 @@
+// 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 "components/mus/public/cpp/tests/window_tree_client_impl_private.h"
+
+#include "components/mus/public/cpp/lib/window_tree_client_impl.h"
+#include "mojo/converters/geometry/geometry_type_converters.h"
+
+namespace mus {
+
+WindowTreeClientImplPrivate::WindowTreeClientImplPrivate(
+    WindowTreeClientImpl* tree_client_impl)
+    : tree_client_impl_(tree_client_impl) {}
+
+WindowTreeClientImplPrivate::~WindowTreeClientImplPrivate() {}
+
+uint32_t WindowTreeClientImplPrivate::event_observer_id() {
+  return tree_client_impl_->event_observer_id_;
+}
+
+void WindowTreeClientImplPrivate::OnEmbed(mojom::WindowTree* window_tree) {
+  mojom::WindowDataPtr root_data(mojom::WindowData::New());
+  root_data->parent_id = 0;
+  root_data->window_id = 1;
+  root_data->bounds = mojo::Rect::From(gfx::Rect());
+  root_data->properties.SetToEmpty();
+  root_data->visible = true;
+  root_data->viewport_metrics = mojom::ViewportMetrics::New();
+  root_data->viewport_metrics->size_in_pixels =
+      mojo::Size::From(gfx::Size(1000, 1000));
+  root_data->viewport_metrics->device_pixel_ratio = 1;
+  tree_client_impl_->OnEmbedImpl(window_tree, 1, std::move(root_data), 0, true);
+}
+
+}  // namespace mus