Handles users rotating screen too early

ash/rotator/screen_rotation_animator.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 ASH_ROTATOR_SCREEN_ROTATION_ANIMATOR_H_
 #define ASH_ROTATOR_SCREEN_ROTATION_ANIMATOR_H_
 
 #include <stdint.h>
 
 #include "ash/ash_export.h"
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "ui/compositor/layer_tree_owner.h"

[bruthig, 2017/03/10 22:34:08]

nit: Can you forward declare this instead?

[wutao, 2017/03/14 16:46:38]

Done.

 #include "ui/display/display.h"
 
 namespace ash {
 
 // Utility to perform a screen rotation with an animation.
 class ASH_EXPORT ScreenRotationAnimator {
  public:
+  class ASH_EXPORT ScreenRotationAnimatorObserver {
+   public:
+    ScreenRotationAnimatorObserver();
+
+    virtual void OnEndedOrAbortedScreenRotationAnimation(
+        ScreenRotationAnimator* animator);
+
+   protected:
+    virtual ~ScreenRotationAnimatorObserver();
+  };
+
+  struct ScreenRotationRequest {

[bruthig, 2017/03/10 22:34:08]

If you make Rotate() a member function, I think you will be able to prune this
struct down to just |new_rotation| and |source|.  And it would probably make
sense to move this struct into the ScreenRotationAnimator class instead of the
Observer at that point.

[wutao, 2017/03/14 16:46:38]

It is already in ScreenRotationAnimator class :)
I will make RotateScreen() a member function.

+    ScreenRotationAnimator* animator;
+    int64_t display_id;
+    display::Display::Rotation initial_rotation;
+    display::Display::Rotation new_rotation;
+    display::Display::RotationSource source;
+  };
+
   explicit ScreenRotationAnimator(int64_t display_id);
   ~ScreenRotationAnimator();
 
-  // Returns true if the screen rotation animation can be completed
-  // successfully. For example an animation is not possible if |display_id_|
-  // specifies a display::Display that is not currently active. See
-  // www.crbug.com/479503.
-  bool CanAnimate() const;
-
   // Rotates the display::Display specified by |display_id_| to the
   // |new_rotation|
   // orientation, for the given |source|. The rotation will also become active.
   // Clients should only call |Rotate()| if |CanAnimate()| returns true.
   void Rotate(display::Display::Rotation new_rotation,

[bruthig, 2017/03/10 22:34:08]

Can you document when the |observer_| will and will not be notified.

[wutao, 2017/03/14 16:46:38]

Done.

               display::Display::RotationSource source);
 
+  int64_t display_id() const { return display_id_; }
+
+  void SetScreenRotationAnimatorObserver(
+      ScreenRotationAnimatorObserver* observer) {
+    screen_rotation_animator_observer_ = observer;
+  }
+
+  void RemoveScreenRotationAnimatorObserver() {
+    screen_rotation_animator_observer_ = nullptr;
+  }
+
+  void set_old_layer_tree_owner(ui::LayerTreeOwner* layer_tree_owner) {

[bruthig, 2017/03/10 22:34:08]

Instead of making set_old_layer_tree_owner() and GetOldLayerTreeRootLayer()
public functions it might make more sense to make the ::RotateScreen() function
in the .cc file a member function.

RotateScreen() might be better named as AnimateRotation() when it's a member
function.

[wutao, 2017/03/14 16:46:38]

Done.

+    old_layer_tree_owner_.reset(layer_tree_owner);
+  }
+
+  // Get the root layer of the old layer tree.
+  ui::Layer* GetOldLayerTreeRootLayer();
+
+  void OnLayerAnimationEnded();
+
+  void OnLayerAnimationAborted();
+
+  bool is_rotating_for_test() const { return is_rotating_; }
+
+  base::WeakPtr<ScreenRotationAnimator> WeakPtr() {
+    return weak_factory_.GetWeakPtr();
+  }
+
  private:
   // The id of the display to rotate.
   int64_t display_id_;
+  bool is_rotating_;
+  ScreenRotationAnimatorObserver* screen_rotation_animator_observer_;
+  std::unique_ptr<ui::LayerTreeOwner> old_layer_tree_owner_;
+  std::unique_ptr<ScreenRotationRequest> last_pending_request_;
+
+  void ContinueOrCleanUp();

[bruthig, 2017/03/10 22:34:08]

Some docs here would be helpful or a rename of ProcessAnimationQueue() might be
a little more self-documenting.

[wutao, 2017/03/14 16:46:38]

Renamed. A doc will be a little redundant when I add the doc for when the
|observer_| will be notified.

+
+  // Aborts the active animations of the layer, and recurses upon its child
+  // layers.
+  void AbortAnimations(ui::Layer* layer);
+
+  void StopAnimating();
+
+  base::WeakPtrFactory<ScreenRotationAnimator> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenRotationAnimator);
 };
 
 }  // namespace ash
 
 #endif  // ASH_ROTATOR_SCREEN_ROTATION_ANIMATOR_H_