Mus: Fixes rendering of transparent containers.

components/mus/ws/test_utils.h

 // 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.
 
 #ifndef COMPONENTS_MUS_WS_TEST_UTILS_H_
 #define COMPONENTS_MUS_WS_TEST_UTILS_H_
 
 #include <stdint.h>
 
 #include <vector>
@@ skipping 208 matching lines @@
   PlatformDisplay* CreatePlatformDisplay() override;
 
  private:
   int32_t* cursor_id_storage_;
 
   DISALLOW_COPY_AND_ASSIGN(TestPlatformDisplayFactory);
 };
 
 // -----------------------------------------------------------------------------
 
+// A stub implementation of FrameGeneratorDelegate.
+class TestFrameGeneratorDelegate : public FrameGeneratorDelegate {
+ public:
+  explicit TestFrameGeneratorDelegate(std::unique_ptr<ServerWindow> root);
+  ~TestFrameGeneratorDelegate() override;
+
+  // FrameGeneratorDelegate:
+  ServerWindow* GetRootWindow() override;
+  void OnCompositorFrameDrawn() override {}
+  const ViewportMetrics& GetViewportMetrics() override;
+
+ private:
+  std::unique_ptr<ServerWindow> root_;
+  ViewportMetrics metrics_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestFrameGeneratorDelegate);
+};
+
+// -----------------------------------------------------------------------------
+
 class TestWindowManager : public mojom::WindowManager {
  public:
   TestWindowManager()
       : got_create_top_level_window_(false),
         change_id_(0u),
         on_accelerator_called_(false),
         on_accelerator_id_(0u) {}
   ~TestWindowManager() override {}
 
   bool did_call_create_top_level_window(uint32_t* change_id) {
@@ skipping 271 matching lines @@
 ServerWindow* NewWindowInTree(WindowTree* tree, ClientWindowId* client_id);
 ServerWindow* NewWindowInTreeWithParent(WindowTree* tree,
                                         ServerWindow* parent,
                                         ClientWindowId* client_id);
 
 }  // namespace test
 }  // namespace ws
 }  // namespace mus
 
 #endif  // COMPONENTS_MUS_WS_TEST_UTILS_H_