Creates mus test helper class

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

Index: components/mus/public/cpp/tests/test_window_tree_connection_setup.cc
diff --git a/components/mus/public/cpp/tests/test_window_tree_connection_setup.cc b/components/mus/public/cpp/tests/test_window_tree_connection_setup.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e1c28350748b1a23bc8bb5fe79383f31fdf6e48f
--- /dev/null
+++ b/components/mus/public/cpp/tests/test_window_tree_connection_setup.cc
@@ -0,0 +1,44 @@
+// 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/test_window_tree_connection_setup.h"
+
+#include "components/mus/public/cpp/lib/window_tree_client_impl.h"
+#include "components/mus/public/cpp/tests/test_window_tree.h"
+#include "components/mus/public/cpp/tests/window_tree_client_impl_private.h"
+
+namespace mus {
+
+TestWindowTreeConnectionSetup::TestWindowTreeConnectionSetup() {}
+
+TestWindowTreeConnectionSetup::~TestWindowTreeConnectionSetup() {
+  std::unique_ptr<WindowTreeConnection> window_tree_client =
+      std::move(window_tree_client_);
+  if (window_tree_client)
+    window_tree_client->RemoveObserver(this);
+}
+
+void TestWindowTreeConnectionSetup::Init(
+    WindowTreeDelegate* window_tree_delegate,
+    WindowManagerDelegate* window_manager_delegate) {
+  window_tree_.reset(new TestWindowTree);
+  window_tree_client_.reset(new WindowTreeClientImpl(
+      window_tree_delegate, window_manager_delegate, nullptr));
+  static_cast<WindowTreeConnection*>(window_tree_client_.get())
+      ->AddObserver(this);
+  WindowTreeClientImplPrivate(window_tree_client_.get())
+      .OnEmbed(window_tree_.get());
+}
+
+WindowTreeConnection* TestWindowTreeConnectionSetup::window_tree_connection() {
+  return window_tree_client_.get();
+}
+
+void TestWindowTreeConnectionSetup::OnWillDestroyConnection(
+    mus::WindowTreeConnection* connection) {
+  // See comment in header as to why we do this.
+  window_tree_client_.release();
+}
+
+}  // namespace mus