mus: Implement interwindow drag and drop

services/ui/ws/current_drag_operation_unittest.cc

+// 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 "services/ui/ws/current_drag_operation_unittest.h"
+
+#include "services/ui/ws/test_server_window_delegate.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+class TestCurrentDragOperationDelegate : public CurrentDragOperationDelegate {
+ public:
+  void OnDragOver(bool success) override { NOTIMPLEMENTED(); }
+};
+
+class CurrentDragOperationTest : public testing::Test,
+                                 public CurrentDragOperationDelegate {
+ public:
+  // Overridden from testing::Test:
+  void SetUp() override {
+    testing::Test::SetUp();
+
+    window_delegate_.reset(new TestServerWindowDelegate());
+    root_window_.reset(
+        new ServerWindow(window_delegate_.get(), WindowId(1, 2)));
+    window_delegate_->set_root_window(root_window_.get());
+    root_window_->SetVisible(true);
+
+    // Big unresolved question here: If we have a ServerWindow, how do we get
+    // back to the WindowTree of the client who owns that ServerWindow? Almost
+    // everything about
+
+    drag_operation_.reset(new CurrentDragOperation(this, ));
+  }
+
+  // Overridden from CurrentDragOperationDelegate:
+  void OnDragOver(bool success) override { NOTIMPLEMENTED(); }
+
+  std::unique_ptr<TestServerWindowDelegate> window_delegate_;
+  std::unique_ptr<ServerWindow> root_window_;
+
+  std::unique_ptr<CurrentDragOperation> drag_operation_;
+};
+
+TEST_F(CurrentDragOperation, DragPointerMove) {
+  // Set up a tree with two overlapping windows.
+  TestServerWindowDelegate window_delegate;
+  ServerWindow window(&window_delegate, WindowId(1, 1));
+}