cros: Adds ShellPort functions for simplified display mode

ash/shell_port.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 ASH_SHELL_PORT_H_
 #define ASH_SHELL_PORT_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <vector>
 
 #include "ash/ash_export.h"
 #include "ash/metrics/gesture_action_type.h"
 #include "ash/metrics/user_metrics_action.h"
 #include "ash/wm/lock_state_observer.h"
 #include "base/observer_list.h"
 #include "ui/base/ui_base_types.h"
 #include "ui/compositor/layer_type.h"
 #include "ui/wm/public/activation_change_observer.h"
 #include "ui/wm/public/window_types.h"
 
 namespace display {
 class Display;
 class ManagedDisplayInfo;
+class NativeDisplayDelegate;
 }
 
 namespace gfx {
 class Insets;
 class Point;
 }
 
 namespace views {
 class PointerWatcher;
 enum class PointerWatcherEventTypes;
 }
 
 namespace ash {
 class AcceleratorController;
+class AshWindowTreeHost;
+struct AshWindowTreeHostInitParams;
 class ImmersiveFullscreenController;
 class KeyEventWatcher;
 class KeyboardUI;
 class RootWindowController;
 class ScopedDisableInternalMouseAndKeyboard;
 class SessionStateDelegate;
 struct ShellInitParams;
 class WindowCycleEventFilter;
 class WindowResizer;
 class WmDisplayObserver;
@@ skipping 147 matching lines @@
   virtual void ToggleIgnoreExternalKeyboard() = 0;
 
   // Enable or disable the laser pointer.
   virtual void SetLaserPointerEnabled(bool enabled) = 0;
 
   // Enable or disable the partial magnifier.
   virtual void SetPartialMagnifierEnabled(bool enabled) = 0;
 
   virtual void CreatePointerWatcherAdapter() = 0;
 
+  // Creates an AshWindowTreeHost. A return value of null results in a platform
+  // specific AshWindowTreeHost being created.
+  virtual AshWindowTreeHost* CreateAshWindowTreeHost(

[James Cook, 2017/04/18 00:43:39]

I think this would be better if it returned unique_ptr<>, even if the caller to
AshWindowTreeHost::Create() had to release() it.

+      const AshWindowTreeHostInitParams& init_params) = 0;
+
  protected:
   ShellPort();
 
   // Called during startup to create the primary WindowTreeHost and
   // the corresponding RootWindowController.
   virtual void CreatePrimaryHost() = 0;
   virtual void InitHosts(const ShellInitParams& init_params) = 0;
+  virtual std::unique_ptr<display::NativeDisplayDelegate>
+  CreateNativeDisplayDelegate() = 0;
 
   // Called during startup to create the AcceleratorController.
   virtual std::unique_ptr<AcceleratorController>
   CreateAcceleratorController() = 0;
 
  private:
   friend class AcceleratorControllerTest;
   friend class Shell;
 
   static ShellPort* instance_;
 
   base::ObserverList<LockStateObserver> lock_state_observers_;
 
   bool simulate_modal_window_open_for_testing_ = false;
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELL_PORT_H_