view_manager.txt

viewstate是数据类，viewimpl是行为类


view_manager::ViewManagerApp app;
  new ViewRegistry(startup_context_.get())
    startup_context_->ConnectToEnvironmentService<fuchsia::ui::scenic::Scenic>()

    Session::Session(fuchsia::ui::scenic::Scenic* scenic)
        scenic->CreateSession(session_.NewRequest(), session_listener_binding_.NewBinding());
            scenic创建的session接口主要是enqueue, present.

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进入scenic进程：
Scenic::CreateSession()
    CreateSessionImmediately(std::move(session_request), std::move(listener));
        Session::Session()

        system->CreateCommandDispatcher(CommandDispatcherContext(this, session.get()));
        GfxSystem::CreateCommandDispatcher()
            engine_->session_manager()->CreateCommandDispatcher(std::move(context),engine_.get());

        session_bindings_.AddBinding(std::move(session), std::move(session_request));
            开始监听了



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ViewRegistry::CreateView
    new ViewState(this, std::move(view_token), std::move(view_request), std::move(view_listener), &session_, SanitizeLabel(label));

    SchedulePresentSession();
        ViewRegistry::PresentSession()
            session_.Present(0, [this](fuchsia::images::PresentationInfo info) {});
                session_->Present(presentation_time, std::move(acquire_fences_),
                    std::move(release_fences_), std::move(callback));
========
Scenic:
Session::Present
    delegate->Present(presentation_time, std::move(acquire_fences), std::move(release_fences), std::move(callback));
        SessionHandler::Present
            session_->ScheduleUpdate
                weak->engine_->session_manager()->ScheduleUpdateForSession
                    update_scheduler->ScheduleUpdate(presentation_time);
                        RenderFrame(FrameTimingsPtr(), presentation_time, 0, false);
                            Compositor::DrawFrame


以上作废
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