Uses copy request to flatten the layers to do screen rotation animation.

ash/rotator/screen_rotation_animator.cc

 // 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.
 
 #include "ash/rotator/screen_rotation_animator.h"
 
 #include <string>
 #include <utility>
 #include <vector>
 
+#include "ash/common/ash_switches.h"
 #include "ash/display/window_tree_host_manager.h"
 #include "ash/rotator/screen_rotation_animation.h"
 #include "ash/rotator/screen_rotation_animator_observer.h"
 #include "ash/shell.h"
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/time/time.h"
+#include "cc/output/copy_output_request.h"
+#include "cc/output/copy_output_result.h"
 #include "ui/aura/window.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_animation_element.h"
 #include "ui/compositor/layer_animation_observer.h"
 #include "ui/compositor/layer_animation_sequence.h"
 #include "ui/compositor/layer_animator.h"
 #include "ui/compositor/layer_owner.h"
 #include "ui/compositor/layer_tree_owner.h"
 #include "ui/display/display.h"
 #include "ui/display/manager/display_manager.h"
@@ skipping 149 matching lines @@
   void Report(int value) override {
     UMA_HISTOGRAM_PERCENTAGE("Ash.Rotation.AnimationSmoothness", value);
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ScreenRotationAnimationMetricsReporter);
 };
 
 }  // namespace
 
-struct ScreenRotationAnimator::ScreenRotationRequest {
-  ScreenRotationRequest(display::Display::Rotation to_rotation,
-                        display::Display::RotationSource from_source)
-      : new_rotation(to_rotation), source(from_source) {}
-  display::Display::Rotation new_rotation;
-  display::Display::RotationSource source;
-};
-
 ScreenRotationAnimator::ScreenRotationAnimator(int64_t display_id)
     : display_id_(display_id),
       is_rotating_(false),
       metrics_reporter_(
           base::MakeUnique<ScreenRotationAnimationMetricsReporter>()),
       disable_animation_timers_for_test_(false),
+      enable_smooth_rotation_for_test_(false),
       weak_factory_(this) {}
 
 ScreenRotationAnimator::~ScreenRotationAnimator() {
   // To prevent a call to |LayerCleanupObserver::OnLayerAnimationAborted()| from
   // calling a method on the |animator_|.
   weak_factory_.InvalidateWeakPtrs();
 
   // Explicitly reset the |old_layer_tree_owner_| and |metrics_reporter_| in
   // order to make sure |metrics_reporter_| outlives the attached animation
   // sequence.
   old_layer_tree_owner_.reset();
   metrics_reporter_.reset();
 }
 
+void ScreenRotationAnimator::StartRotationAnimation(
+    std::unique_ptr<ScreenRotationRequest> rotation_request) {
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kAshEnableSmoothScreenRotation) ||
+      enable_smooth_rotation_for_test_) {

[oshima, 2017/04/04 20:23:13]

you can just add the switch in the test.

[wutao, 2017/04/05 00:09:22]

Done.

+    RequestCopyRootLayerAndAnimateRotation(std::move(rotation_request));
+  } else {
+    CreateOldLayerTree();
+    AnimateRotation(std::move(rotation_request));
+  }
+}
+
+void ScreenRotationAnimator::RequestCopyRootLayerAndAnimateRotation(
+    std::unique_ptr<ScreenRotationRequest> rotation_request) {
+  std::unique_ptr<cc::CopyOutputRequest> copy_output_request =
+      CreateAfterCopyCallback(std::move(rotation_request));
+  ui::Layer* layer = GetRootWindow(display_id_)->layer();
+  copy_output_request->set_area(gfx::Rect(layer->size()));
+  layer->RequestCopyOfOutput(std::move(copy_output_request));
+}
+
+std::unique_ptr<cc::CopyOutputRequest>
+ScreenRotationAnimator::CreateAfterCopyCallback(
+    std::unique_ptr<ScreenRotationRequest> rotation_request) {
+  return cc::CopyOutputRequest::CreateRequest(
+      base::Bind(&ScreenRotationAnimator::OnRootLayerCopiedBeforeRotation,
+                 weak_factory_.GetWeakPtr(), base::Passed(&rotation_request)));
+}
+
+void ScreenRotationAnimator::OnRootLayerCopiedBeforeRotation(
+    std::unique_ptr<ScreenRotationRequest> rotation_request,
+    std::unique_ptr<cc::CopyOutputResult> result) {
+  // If display was removed, should abort rotation.
+  if (!IsDisplayIdValid(display_id_)) {
+    ProcessAnimationQueue();
+    return;
+  }
+  // Fall back to recreate layers solution when the copy request has been
+  // canceled or failed. It would fail if, for examples: a) The layer is removed
+  // from the compositor and destroyed before committing the request to the
+  // compositor. b) The compositor is shutdown.
+  if (result->IsEmpty())
+    CreateOldLayerTree();
+  else
+    CopyOldLayerTree(std::move(result));
+  AnimateRotation(std::move(rotation_request));
+}
+
+void ScreenRotationAnimator::CreateOldLayerTree() {
+  old_layer_tree_owner_ = ::wm::RecreateLayers(GetRootWindow(display_id_));
+}
+
+void ScreenRotationAnimator::CopyOldLayerTree(
+    std::unique_ptr<cc::CopyOutputResult> result) {
+  cc::TextureMailbox texture_mailbox;
+  std::unique_ptr<cc::SingleReleaseCallback> release_callback;
+  result->TakeTexture(&texture_mailbox, &release_callback);
+  DCHECK(texture_mailbox.IsTexture());
+
+  aura::Window* root_window = GetRootWindow(display_id_);
+  gfx::Rect rect(root_window->layer()->size());
+  std::unique_ptr<ui::Layer> copy_layer = base::MakeUnique<ui::Layer>();
+  copy_layer->SetBounds(rect);
+  copy_layer->SetTextureMailbox(texture_mailbox, std::move(release_callback),
+                                rect.size());
+  old_layer_tree_owner_ =
+      base::MakeUnique<ui::LayerTreeOwner>(std::move(copy_layer));
+}
+
 void ScreenRotationAnimator::AnimateRotation(
     std::unique_ptr<ScreenRotationRequest> rotation_request) {
   aura::Window* root_window = GetRootWindow(display_id_);
+  std::unique_ptr<LayerCleanupObserver> old_layer_cleanup_observer(
+      new LayerCleanupObserver(weak_factory_.GetWeakPtr()));
+  ui::Layer* old_root_layer = old_layer_tree_owner_->root();
+  old_root_layer->set_name("ScreenRotationAnimator:old_layer_tree");
+  // Add the cloned layer tree in to the root, so it will be rendered.
+  root_window->layer()->Add(old_root_layer);
+  root_window->layer()->StackAtTop(old_root_layer);
 
   const gfx::Rect original_screen_bounds = root_window->GetTargetBounds();
 
   const int rotation_factor = GetRotationFactor(
       GetCurrentScreenRotation(display_id_), rotation_request->new_rotation);
 
   const int old_layer_initial_rotation_degrees = GetInitialDegrees(
       GetCurrentScreenRotation(display_id_), rotation_request->new_rotation);
 
   const base::TimeDelta duration =
       base::TimeDelta::FromMilliseconds(kRotationDurationInMs);
 
   const gfx::Tween::Type tween_type = gfx::Tween::FAST_OUT_LINEAR_IN;
 
-  std::unique_ptr<ui::LayerTreeOwner> old_layer_tree =
-      ::wm::RecreateLayers(root_window);
-  old_layer_tree->root()->set_name("ScreenRotationAnimator:old_layer_tree");
-
-  // Add the cloned layer tree in to the root, so it will be rendered.
-  root_window->layer()->Add(old_layer_tree->root());
-  root_window->layer()->StackAtTop(old_layer_tree->root());
-
-  old_layer_tree_owner_ = std::move(old_layer_tree);
-  std::unique_ptr<LayerCleanupObserver> old_layer_cleanup_observer(
-      new LayerCleanupObserver(weak_factory_.GetWeakPtr()));
-
   Shell::GetInstance()->display_manager()->SetDisplayRotation(
       display_id_, rotation_request->new_rotation, rotation_request->source);
 
   const gfx::Rect rotated_screen_bounds = root_window->GetTargetBounds();
   const gfx::Point pivot = gfx::Point(rotated_screen_bounds.width() / 2,
                                       rotated_screen_bounds.height() / 2);
 
-  ui::Layer* old_root_layer = old_layer_tree_owner_->root();
   // We must animate each non-cloned child layer individually because the cloned
   // layer was added as a child to |root_window|'s layer so that it will be
   // rendered.
   // TODO(bruthig): Add a NOT_DRAWN layer in between the root_window's layer and
   // its current children so that we only need to initiate two
   // LayerAnimationSequences. One for the new layers and one for the old layer.
   for (ui::Layer* child_layer : root_window->layer()->children()) {
     // Skip the cloned layer because it has a different animation.
     if (child_layer == old_root_layer)
       continue;
@@ skipping 58 matching lines @@
       base::MakeUnique<ScreenRotationRequest>(new_rotation, source);
 
   if (is_rotating_) {
     last_pending_request_ = std::move(rotation_request);
     // The pending request will be processed when the
     // OnLayerAnimation(Ended|Aborted) methods should be called after
     // StopAnimating().
     StopAnimating();
   } else {
     is_rotating_ = true;
-    AnimateRotation(std::move(rotation_request));
+    StartRotationAnimation(std::move(rotation_request));
   }
 }
 
 void ScreenRotationAnimator::AddScreenRotationAnimatorObserver(
     ScreenRotationAnimatorObserver* observer) {
   screen_rotation_animator_observers_.AddObserver(observer);
 }
 
 void ScreenRotationAnimator::RemoveScreenRotationAnimatorObserver(
     ScreenRotationAnimatorObserver* observer) {
@@ skipping 13 matching lines @@
 
   for (auto& observer : screen_rotation_animator_observers_)
     observer.OnScreenRotationAnimationFinished(this);
 }
 
 void ScreenRotationAnimator::set_disable_animation_timers_for_test(
     bool disable_timers) {
   disable_animation_timers_for_test_ = disable_timers;
 }
 
+void ScreenRotationAnimator::set_enable_smooth_rotation_for_test(
+    bool enable_smooth_rotation) {
+  enable_smooth_rotation_for_test_ = enable_smooth_rotation;
+}
+
 void ScreenRotationAnimator::StopAnimating() {
   aura::Window* root_window = GetRootWindow(display_id_);
   for (ui::Layer* child_layer : root_window->layer()->children()) {
     if (child_layer == old_layer_tree_owner_->root())
       continue;
 
     child_layer->GetAnimator()->StopAnimating();
   }
 
   old_layer_tree_owner_->root()->GetAnimator()->StopAnimating();
 }
 
 }  // namespace ash