splitview: Change highlights to use a single solid color layer.

Replaces the old three view setup which was used before we could
apply rounded corners directly on layers. Tested manually on
LTR and RTL on all 4 orientations. Visually no difference.

Ran ui.OverviewDragWindowPerf.drag_to_snap. Not noticeable
improvements on caroline, but input latency goes from 95ms to 80ms
on krane.

Test: added tests
Bug: 1047778
Change-Id: Idff6345fb5778d2e898bc51cd76bd7eac3c1741d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2033564
Commit-Queue: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738262}

ash/BUILD.gn

@@ -2353,8 +2353,6 @@ static_library("test_support") {
     "wm/lock_state_controller_test_api.h",
     "wm/splitview/multi_display_overview_and_split_view_test.cc",
     "wm/splitview/multi_display_overview_and_split_view_test.h",
-    "wm/splitview/split_view_highlight_view_test_api.cc",
-    "wm/splitview/split_view_highlight_view_test_api.h",
     "wm/tablet_mode/tablet_mode_controller_test_api.cc",
     "wm/tablet_mode/tablet_mode_controller_test_api.h",
     "wm/test_activation_delegate.cc",

ash/wm/splitview/split_view_drag_indicators.cc

@@ -236,11 +236,6 @@ class SplitViewDragIndicators::SplitViewDragIndicatorsView
     right_highlight_view_ = AddChildView(
         std::make_unique<SplitViewHighlightView>(/*is_right_or_bottom=*/true));
 
-    left_highlight_view_->SetPaintToLayer();
-    right_highlight_view_->SetPaintToLayer();
-    left_highlight_view_->layer()->SetFillsBoundsOpaquely(false);
-    right_highlight_view_->layer()->SetFillsBoundsOpaquely(false);
-
     left_rotated_view_ = AddChildView(
         std::make_unique<RotatedImageLabelView>(/*is_right_or_bottom=*/false));
     right_rotated_view_ = AddChildView(
@@ -464,9 +459,8 @@ class SplitViewDragIndicators::SplitViewDragIndicatorsView
     }
 
     left_highlight_view_->SetBounds(GetMirroredRect(left_highlight_bounds),
-                                    horizontal, left_highlight_animation_type);
+                                    left_highlight_animation_type);
     right_highlight_view_->SetBounds(GetMirroredRect(right_highlight_bounds),
-                                     horizontal,
                                      right_highlight_animation_type);
 
     // Calculate the bounds of the views which contain the guidance text and

ash/wm/splitview/split_view_highlight_view.h

@@ -13,37 +13,23 @@
 
 namespace ash {
 
-class RoundedRectView;
-class SplitViewHighlightViewTestApi;
-
 // View that is used for displaying and animating the highlights which tell
 // users where to drag windows to enter splitview, and previews the space which
-// a snapped window will occupy. It is a view consisting of a rectangle with
-// rounded corners on the left or top, a rectangle in the middle and a rectangle
-// with rounded corners on the right or bottom. It is done this way to ensure
-// rounded corners remain the same during the duration of an animation.
-// (Transforming a rounded rect will stretch the corners, and having to repaint
-// every animation tick is expensive.)
-//
-// Although rounded corners are prevented from stretching along one axis, there
-// is one animation where the rounded corners will stretch along the
-// perpendicular axis. Specifically, the preview area has a small inset (on all
-// four sides) until you actually snap the window, and then the preview area
-// animates to nix that inset while fading out. So the rounded corners will
-// stretch by an amount depending on the dimensions of the work area, but it is
-// unlikely to be noticeable under normal circumstances.
+// a snapped window will occupy. It is a view consists of one solid color layer
+// with rounded corners. If animations are needed, they are performed by
+// animating the layer's clip rect.
 class ASH_EXPORT SplitViewHighlightView : public views::View {
  public:
   explicit SplitViewHighlightView(bool is_right_or_bottom);
   ~SplitViewHighlightView() override;
 
+  SplitViewHighlightView(const SplitViewHighlightView&) = delete;
+  SplitViewHighlightView& operator=(const SplitViewHighlightView&) = delete;
+
   // Updates bounds, animating if |animation_type| has a value.
   void SetBounds(const gfx::Rect& bounds,
-                 bool landscape,
                  const base::Optional<SplitviewAnimationType>& animation_type);
 
-  void SetColor(SkColor color);
-
   // Called to update the opacity of the highlights view on transition from
   // |previous_window_dragging_state| to |window_dragging_state|. If
   // |previews_only|, then there shall be no visible drag indicators except for
@@ -57,21 +43,11 @@ class ASH_EXPORT SplitViewHighlightView : public views::View {
       bool can_dragged_window_be_snapped);
 
  private:
-  friend class SplitViewHighlightViewTestApi;
-
-  // The three components of this view.
-  RoundedRectView* left_top_ = nullptr;
-  RoundedRectView* right_bottom_ = nullptr;
-  views::View* middle_ = nullptr;
-
-  bool landscape_ = true;
   // Determines whether this particular highlight view is located at the right
   // or bottom of the screen. These highlights animate in the opposite direction
-  // as left or top highlights, so when we use SetBounds extra calucations have
-  // to be done to ensure the animation is correct.
+  // as left or top highlights, so when we use |SetBounds()| extra calucations
+  // have to be done to ensure the animation is correct.
   const bool is_right_or_bottom_;
-
-  DISALLOW_COPY_AND_ASSIGN(SplitViewHighlightView);
 };
 
 }  // namespace ash

ash/wm/splitview/split_view_highlight_view_test_api.cc

-// Copyright 2018 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/wm/splitview/split_view_highlight_view_test_api.h"
-
-#include "ash/wm/overview/rounded_rect_view.h"
-#include "ui/views/view.h"
-
-namespace ash {
-
-SplitViewHighlightViewTestApi::SplitViewHighlightViewTestApi(
-    SplitViewHighlightView* highlight_view)
-    : highlight_view_(highlight_view) {}
-
-SplitViewHighlightViewTestApi::~SplitViewHighlightViewTestApi() = default;
-
-views::View* SplitViewHighlightViewTestApi::GetLeftTopView() {
-  return static_cast<views::View*>(highlight_view_->left_top_);
-}
-
-views::View* SplitViewHighlightViewTestApi::GetRightBottomView() {
-  return static_cast<views::View*>(highlight_view_->right_bottom_);
-}
-
-views::View* SplitViewHighlightViewTestApi::GetMiddleView() {
-  return highlight_view_->middle_;
-}
-
-}  // namespace ash

ash/wm/splitview/split_view_highlight_view_test_api.h

-// Copyright 2018 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_WM_SPLITVIEW_SPLIT_VIEW_HIGHLIGHT_VIEW_TEST_API_H_
-#define ASH_WM_SPLITVIEW_SPLIT_VIEW_HIGHLIGHT_VIEW_TEST_API_H_
-
-#include "ash/wm/splitview/split_view_highlight_view.h"
-#include "base/macros.h"
-
-namespace views {
-class View;
-}  // namespace views
-
-namespace ash {
-
-// Use the api in this class to test SplitViewHighlightView.
-class SplitViewHighlightViewTestApi {
- public:
-  explicit SplitViewHighlightViewTestApi(
-      SplitViewHighlightView* highlight_view);
-  ~SplitViewHighlightViewTestApi();
-
-  views::View* GetLeftTopView();
-  views::View* GetRightBottomView();
-  views::View* GetMiddleView();
-
- private:
-  SplitViewHighlightView* highlight_view_;
-
-  DISALLOW_COPY_AND_ASSIGN(SplitViewHighlightViewTestApi);
-};
-
-}  // namespace ash
-
-#endif  // ASH_WM_SPLITVIEW_SPLIT_VIEW_HIGHLIGHT_VIEW_TEST_API_H_

ash/wm/splitview/split_view_utils.cc

@@ -243,13 +243,9 @@ void DoSplitviewTransformAnimation(
     return;
 
   switch (type) {
-    case SPLITVIEW_ANIMATION_OTHER_HIGHLIGHT_SLIDE_IN:
-    case SPLITVIEW_ANIMATION_OTHER_HIGHLIGHT_SLIDE_OUT:
     case SPLITVIEW_ANIMATION_OTHER_HIGHLIGHT_TEXT_SLIDE_IN:
     case SPLITVIEW_ANIMATION_OTHER_HIGHLIGHT_TEXT_SLIDE_OUT:
     case SPLITVIEW_ANIMATION_PREVIEW_AREA_NIX_INSET:
-    case SPLITVIEW_ANIMATION_PREVIEW_AREA_SLIDE_IN:
-    case SPLITVIEW_ANIMATION_PREVIEW_AREA_SLIDE_OUT:
     case SPLITVIEW_ANIMATION_PREVIEW_AREA_TEXT_SLIDE_IN:
     case SPLITVIEW_ANIMATION_PREVIEW_AREA_TEXT_SLIDE_OUT:
     case SPLITVIEW_ANIMATION_SET_WINDOW_TRANSFORM:
@@ -276,6 +272,42 @@ void DoSplitviewTransformAnimation(
   layer->SetTransform(target_transform);
 }
 
+void DoSplitviewClipRectAnimation(
+    ui::Layer* layer,
+    SplitviewAnimationType type,
+    const gfx::Rect& target_clip_rect,
+    std::unique_ptr<ui::ImplicitAnimationObserver> animation_observer) {
+  ui::LayerAnimator* animator = layer->GetAnimator();
+  if (animator->GetTargetClipRect() == target_clip_rect)
+    return;
+
+  switch (type) {
+    case SPLITVIEW_ANIMATION_OTHER_HIGHLIGHT_SLIDE_IN:
+    case SPLITVIEW_ANIMATION_OTHER_HIGHLIGHT_SLIDE_OUT:
+    case SPLITVIEW_ANIMATION_PREVIEW_AREA_NIX_INSET:
+    case SPLITVIEW_ANIMATION_PREVIEW_AREA_SLIDE_IN:
+    case SPLITVIEW_ANIMATION_PREVIEW_AREA_SLIDE_OUT:
+      break;
+    default:
+      NOTREACHED() << "Not a valid split view clip rect type.";
+      return;
+  }
+
+  base::TimeDelta duration;
+  gfx::Tween::Type tween;
+  ui::LayerAnimator::PreemptionStrategy preemption_strategy;
+  base::TimeDelta delay;
+  GetAnimationValuesForType(type, &duration, &tween, &preemption_strategy,
+                            &delay);
+
+  ui::ScopedLayerAnimationSettings settings(animator);
+  if (animation_observer.get())
+    settings.AddObserver(animation_observer.release());
+  ApplyAnimationSettings(&settings, animator, ui::LayerAnimationElement::CLIP,
+                         duration, tween, preemption_strategy, delay);
+  layer->SetClipRect(target_clip_rect);
+}
+
 void MaybeRestoreSplitView(bool refresh_snapped_windows) {
   if (!ShouldAllowSplitView() ||
       !Shell::Get()->tablet_mode_controller()->InTabletMode()) {

ash/wm/splitview/split_view_utils.h

@@ -112,6 +112,13 @@ void DoSplitviewTransformAnimation(
     const gfx::Transform& target_transform,
     std::unique_ptr<ui::ImplicitAnimationObserver> animation_observer);
 
+// Animates |layer|'s clip rect based on |type|.
+void DoSplitviewClipRectAnimation(
+    ui::Layer* layer,
+    SplitviewAnimationType type,
+    const gfx::Rect& target_clip_rect,
+    std::unique_ptr<ui::ImplicitAnimationObserver> animation_observer);
+
 // Restores split view and overview based on the current split view's state.
 // If |refresh_snapped_windows| is true, it will update the left and right
 // snapped windows based on the MRU windows snapped states.