Refactor Mus demo to prepare support for multiple external windows

services/ui/demo/mus_demo.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/demo/mus_demo.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/time/time.h"
 #include "services/service_manager/public/cpp/connector.h"
 #include "services/service_manager/public/cpp/service_context.h"
@@ skipping 49 matching lines @@
     canvas->rotate(angle);
     canvas->translate(-SkFloatToScalar(canvas_size.width() * 0.5f),
                       -SkFloatToScalar(canvas_size.height() * 0.5f));
   }
 
   canvas->drawRect(rect, paint);
 }
 
 }  // namespace
 
+class MusDemo::WindowTreeData {
+ public:
+  explicit WindowTreeData(
+      std::unique_ptr<aura::WindowTreeHostMus> window_tree_host);
+  ~WindowTreeData();
+
+ private:
+  // Draws one frame, incrementing the rotation angle.
+  void DrawFrame();
+
+  // The Window tree host corresponding to this data.
+  std::unique_ptr<aura::WindowTreeHostMus> window_tree_host_;
+
+  // Root window of the window tree host.
+  aura::Window* root_window_ = nullptr;

[sky, 2017/02/09 20:53:16]

Why do you need to cache this? window_tree_host_->window() gives you the root.

+
+  // Window to which we draw the bitmap.
+  std::unique_ptr<aura::Window> bitmap_window_;

[sky, 2017/02/09 20:53:16]

Windows are generally owned by their parent. Are you sure you need a unique_ptr
here?

+
+  // Destroys itself when the window gets destroyed.
+  aura_extra::ImageWindowDelegate* window_delegate_ = nullptr;
+
+  // Timer for calling DrawFrame().
+  base::RepeatingTimer timer_;
+
+  // Current rotation angle for drawing.
+  double angle_ = 0.0;
+
+  // Last time a frame was drawn.
+  base::TimeTicks last_draw_frame_time_;
+};

[sky, 2017/02/09 20:53:16]

DISALLOW...

+
 MusDemo::MusDemo() {}
 
 MusDemo::~MusDemo() {
   display::Screen::SetScreenInstance(nullptr);
 }
 
 void MusDemo::OnStart() {
   screen_ = base::MakeUnique<display::ScreenBase>();
   display::Screen::SetScreenInstance(screen_.get());
 
@@ skipping 23 matching lines @@
 void MusDemo::OnUnembed(aura::Window* root) {
   NOTREACHED();
 }
 
 void MusDemo::OnEmbedRootDestroyed(aura::WindowTreeHostMus* window_tree_host) {
   // Not called for the WindowManager.
   NOTREACHED();
 }
 
 void MusDemo::OnLostConnection(aura::WindowTreeClient* client) {
-  root_window_ = nullptr;
   window_tree_client_.reset();
-  timer_.Stop();
+  window_tree_data_.reset();
 }
 
 void MusDemo::OnPointerEventObserved(const PointerEvent& event,
                                      aura::Window* target) {}
 
 aura::PropertyConverter* MusDemo::GetPropertyConverter() {
   return property_converter_.get();
 }
 
 void MusDemo::SetWindowManagerClient(aura::WindowManagerClient* client) {}
@@ skipping 24 matching lines @@
 }
 
 void MusDemo::OnWmWillCreateDisplay(const display::Display& display) {
   screen_->display_list().AddDisplay(display,
                                      display::DisplayList::Type::PRIMARY);
 }
 
 void MusDemo::OnWmNewDisplay(
     std::unique_ptr<aura::WindowTreeHostMus> window_tree_host,
     const display::Display& display) {
-  DCHECK(!root_window_);  // Only support one display.
+  DCHECK(!window_tree_data_);  // Only support one display.
+  window_tree_data_ =
+      base::MakeUnique<WindowTreeData>(std::move(window_tree_host));
+}
 
+MusDemo::WindowTreeData::WindowTreeData(
+    std::unique_ptr<aura::WindowTreeHostMus> window_tree_host) {
   window_tree_host->InitHost();
   window_tree_host->Show();
   root_window_ = window_tree_host->window();
   // Take ownership of the WTH.
   window_tree_host_ = std::move(window_tree_host);
 
   // Initialize the window for the bitmap.
   window_delegate_ = new aura_extra::ImageWindowDelegate();
   bitmap_window_ = base::MakeUnique<aura::Window>(window_delegate_);
   bitmap_window_->Init(LAYER_TEXTURED);
   bitmap_window_->SetBounds(root_window_->bounds());
   bitmap_window_->Show();
   bitmap_window_->SetName("Bitmap");
 
   root_window_->AddChild(bitmap_window_.get());
 
   // Draw initial frame and start the timer to regularly draw frames.
   DrawFrame();
   timer_.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(kFrameDelay),
-               base::Bind(&MusDemo::DrawFrame, base::Unretained(this)));
+               base::Bind(&WindowTreeData::DrawFrame, base::Unretained(this)));
 }
 
 void MusDemo::OnWmDisplayRemoved(aura::WindowTreeHostMus* window_tree_host) {
+  window_tree_data_.reset();
+}
+
+MusDemo::WindowTreeData::~WindowTreeData() {
   timer_.Stop();
   root_window_->RemoveChild(bitmap_window_.get());
   bitmap_window_.reset();
 }
 
 void MusDemo::OnWmDisplayModified(const display::Display& display) {}
 
 mojom::EventResult MusDemo::OnAccelerator(uint32_t id, const Event& event) {
   return mojom::EventResult::UNHANDLED;
 }
 
 void MusDemo::OnWmPerformMoveLoop(aura::Window* window,
                                   mojom::MoveLoopSource source,
                                   const gfx::Point& cursor_location,
                                   const base::Callback<void(bool)>& on_done) {
   // Don't care
 }
 
 void MusDemo::OnWmCancelMoveLoop(aura::Window* window) {}
 
 void MusDemo::OnWmSetClientArea(
     aura::Window* window,
     const gfx::Insets& insets,
     const std::vector<gfx::Rect>& additional_client_areas) {}
 
 bool MusDemo::IsWindowActive(aura::Window* window) { return false; }
 
 void MusDemo::OnWmDeactivateWindow(aura::Window* window) {}
 
-void MusDemo::DrawFrame() {
+void MusDemo::WindowTreeData::DrawFrame() {
   base::TimeTicks now = base::TimeTicks::Now();
 
   VLOG(1) << (now - last_draw_frame_time_).InMilliseconds()
           << "ms since the last frame was drawn.";
   last_draw_frame_time_ = now;
 
   angle_ += 2.0;
   if (angle_ >= 360.0)
     angle_ = 0.0;
 
@@ skipping 15 matching lines @@
   gfx::ImageSkiaRep image_skia_rep(bitmap, 1);
   gfx::ImageSkia image_skia(image_skia_rep);
   gfx::Image image(image_skia);
 
   window_delegate_->SetImage(image);
   bitmap_window_->SchedulePaintInRect(bitmap_window_->bounds());
 }
 
 }  // namespace demo
 }  // namespace aura