Add second copy request after screen rotation to flatten the layers in animation.

ash/rotator/screen_rotation_animator.h

Index: ash/rotator/screen_rotation_animator.h
diff --git a/ash/rotator/screen_rotation_animator.h b/ash/rotator/screen_rotation_animator.h
index ce77673d356d949614e4d4f6714cc5ee5bc0b357..4788bfce59764d3d6832703414bc445bfc56f815 100644
--- a/ash/rotator/screen_rotation_animator.h
+++ b/ash/rotator/screen_rotation_animator.h
@@ -14,13 +14,19 @@
 #include "base/observer_list.h"
 #include "ui/display/display.h"
 
+namespace aura {
+class Window;
+}  // namesapce aura
+
 namespace cc {
+class CopyOutputRequest;
 class CopyOutputResult;
 }  // namespace cc
 
 namespace ui {
 class AnimationMetricsReporter;
 class Layer;
+class LayerOwner;
 class LayerTreeOwner;
 }  // namespace ui
 
@@ -69,13 +75,19 @@ class ASH_EXPORT ScreenRotationAnimator {
                           display::Display::RotationSource from_source)
         : id(id), new_rotation(to_rotation), source(from_source) {}
     int64_t id;
+    display::Display::Rotation old_rotation;
     display::Display::Rotation new_rotation;
     display::Display::RotationSource source;
   };
 
   // This function can be overridden in unit test to test removing external
   // display.
-  virtual CopyCallback CreateAfterCopyCallback(
+  virtual CopyCallback CreateAfterCopyCallbackBeforeRotation(
+      std::unique_ptr<ScreenRotationRequest> rotation_request);
+
+  // This function can be overridden in unit test to test removing external
+  // display.
+  virtual CopyCallback CreateAfterCopyCallbackAfterRotation(
       std::unique_ptr<ScreenRotationRequest> rotation_request);
 
  private:
@@ -84,20 +96,44 @@ class ASH_EXPORT ScreenRotationAnimator {
   void StartRotationAnimation(
       std::unique_ptr<ScreenRotationRequest> rotation_request);
 
-  // This is an asynchronous call to request copy output of root layer.
-  void RequestCopyRootLayerAndAnimateRotation(
+  // The code path to start "slow animation". The difference between the "slow"
+  // and "smooth" animation, is that "slow animation" will recreate all the
+  // layers before rotation and use the recreated layers and rotated layers for
+  // cross-fading animation. This is slow by adding multiple layer animation
+  // elements. The "smooth animation" copies the layer output before and after
+  // rotation, and use them for cross-fading animation. The output copy layer
+  // flatten the layer hierarchy and makes the animation smooth.
+  void StartSlowAnimation(
       std::unique_ptr<ScreenRotationRequest> rotation_request);
 
-  // The callback in |RequestCopyRootLayerAndAnimateRotation()|.
-  void OnRootLayerCopiedBeforeRotation(
+  // A wrapper to call |display_manager| to set screen rotation and rotate the
+  // |old_layer_tree| to the |old_rotation|.
+  void SetRotation(display::Display::Rotation old_rotation,
+                   display::Display::Rotation new_rotation,
+                   display::Display::RotationSource source);
+
+  // This is an asynchronous call to request copy output of root layer.
+  void RequestCopyScreenRotationContainerLayer(
+      std::unique_ptr<cc::CopyOutputRequest> copy_output_request);
+
+  // The callback in |RequestCopyScreenRotationContainerLayer()| before screen
+  // rotation.
+  void OnScreenRotationContainerLayerCopiedBeforeRotation(
       std::unique_ptr<ScreenRotationRequest> rotation_request,
       std::unique_ptr<cc::CopyOutputResult> result);
 
-  // Recreates all |root_window| layers.
-  void CreateOldLayerTree();
+  // The callback in |RequestCopyScreenRotationContainerLayer()| after screen
+  // rotation.
+  void OnScreenRotationContainerLayerCopiedAfterRotation(
+      std::unique_ptr<ScreenRotationRequest> rotation_request,
+      std::unique_ptr<cc::CopyOutputResult> result);
 
-  // Requests a copy of |root_window| root layer output.
-  void CopyOldLayerTree(std::unique_ptr<cc::CopyOutputResult> result);
+  // Recreates all |root_window| layers and their layer tree owner.
+  void CreateOldLayerTreeForSlowAnimation();
+
+  // Creates a new layer and its layer tree owner from |CopyOutputResult|.
+  std::unique_ptr<ui::LayerTreeOwner> CopyLayerTree(
+      std::unique_ptr<cc::CopyOutputResult> result);
 
   // Note: Only call this function when the |old_layer_tree_owner_| is set up
   // properly.
@@ -108,7 +144,13 @@ class ASH_EXPORT ScreenRotationAnimator {
   // |rotation_degrees| arc.
   void AnimateRotation(std::unique_ptr<ScreenRotationRequest> rotation_request);
 
-  void set_disable_animation_timers_for_test(bool disable_timers);
+  void set_disable_animation_timers_for_test(bool disable_timers) {
+    disable_animation_timers_for_test_ = disable_timers;
+  }
+
+  void set_switch_smooth_rotation_for_test(bool enable) {
+    has_switch_ash_enable_smooth_screen_rotation_ = enable;
+  }

[oshima, 2017/04/19 22:56:52]

last one. instead, just append switch in the SetUp in the test. 
You can have test base class for slow (no switch), and fast (with swtich). 

[wutao, 2017/04/20 00:32:52]

Separate the two test sets for slow/smooth animation.

 
   void StopAnimating();
 
@@ -135,7 +177,12 @@ class ASH_EXPORT ScreenRotationAnimator {
   base::ObserverList<ScreenRotationAnimatorObserver>
       screen_rotation_animator_observers_;
   std::unique_ptr<ui::LayerTreeOwner> old_layer_tree_owner_;
+  std::unique_ptr<ui::LayerTreeOwner> new_layer_tree_owner_;
+  std::unique_ptr<ui::LayerOwner> black_mask_layer_owner_;
   std::unique_ptr<ScreenRotationRequest> last_pending_request_;
+  bool has_switch_ash_enable_smooth_screen_rotation_;
+  aura::Window* root_window_;
+  ui::Layer* screen_rotation_container_layer_;
   base::WeakPtrFactory<ScreenRotationAnimator> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenRotationAnimator);