Mozart: Move frame lag compensation to new class.

mojo/ui/choreographer.h

 // Copyright 2015 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 MOJO_UI_CHOREOGRAPHER_H_
 #define MOJO_UI_CHOREOGRAPHER_H_
 
 #include "base/time/time.h"
 #include "mojo/public/cpp/system/macros.h"
+#include "mojo/services/gfx/composition/cpp/frame_tracker.h"
 #include "mojo/services/gfx/composition/interfaces/scenes.mojom.h"
 #include "mojo/services/gfx/composition/interfaces/scheduling.mojom.h"
 
 namespace mojo {
 namespace ui {
 
 class ChoreographerDelegate;
 
 // Coordinates drawing a frame of a scene.
 //
 // This class is intended to be included as a member of a View that wants to
 // schedule drawing using the following pattern.
 //
 // class MyView : public mojo::ui::BaseView,
 //                public mojo::ui::ChoreographerDelegate {
 //  public:
 //   MyView(mojo::ApplicationImpl* app_impl,
 //          const mojo::ui::ViewProvider::CreateViewCallback&
 //              create_view_callback)
 //          : BaseView(app_impl, "MyView", create_view_callback),
-//            choreographer_(scene_scheduler(), this) {}
+//            choreographer_(scene(), this) {}
 //   ~MyView() override {}
 //
 //  private:
 //   // |ChoreographerDelegate|:
 //   void OnDraw(const mojo::gfx::composition::FrameInfo& frame_info) override;
 //
 //   mojo::ui::Choreographer choreographer_;
 //
 //   MOJO_DISALLOW_COPY_AND_ASSIGN(MyView);
 // };
 class Choreographer {
  public:
   Choreographer(mojo::gfx::composition::Scene* scene,
                 ChoreographerDelegate* delegate);
   Choreographer(mojo::gfx::composition::SceneSchedulerPtr scene_scheduler,
                 ChoreographerDelegate* delegate);
   ~Choreographer();
 
   // Gets the scene scheduler.
   mojo::gfx::composition::SceneScheduler* scene_scheduler() {
     return scene_scheduler_.get();
   }
 
-  // Gets the most recent frame info, or null if none.
-  mojo::gfx::composition::FrameInfo* last_frame_info() {
-    return last_frame_info_.get();
+  // Gets the frame tracker.
+  mojo::gfx::composition::FrameTracker& frame_tracker() {
+    return frame_tracker_;
   }
 
   // Schedules a call to the delegate's |OnDraw| using the scene scheduler.
   void ScheduleDraw();
 
  private:
   mojo::gfx::composition::SceneSchedulerPtr scene_scheduler_;
   ChoreographerDelegate* delegate_;
-  mojo::gfx::composition::FrameInfoPtr last_frame_info_;
+  mojo::gfx::composition::FrameTracker frame_tracker_;
 
   void ScheduleFrame();
   void DoFrame(mojo::gfx::composition::FrameInfoPtr frame_info);
 
   bool draw_scheduled_ = false;
   bool frame_scheduled_ = false;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(Choreographer);
 };
 
@@ skipping 13 matching lines @@
                       const base::TimeDelta& time_delta) = 0;
 
  private:
   MOJO_DISALLOW_COPY_AND_ASSIGN(ChoreographerDelegate);
 };
 
 }  // namespace ui
 }  // namespace mojo
 
 #endif  // MOJO_UI_CHOREOGRAPHER_H_