overview: Modify header clipping.

If a window is not animated, clipping will happen on first bounds update
and without animation. Windows animated into overview remain unchanged.

See bug for before and after videos [1].

[1] https://bugs.chromium.org/p/chromium/issues/detail?id=1069540#c11

Test: manual
Bug: 1069540
Change-Id: I683b49e87c5fa4fe0bc6d27b2dee31389fbb0d32
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2145233
Commit-Queue: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758231}

ash/wm/overview/overview_item.cc

@@ -281,8 +281,9 @@ gfx::RectF OverviewItem::GetTransformedBounds() const {
 void OverviewItem::SetBounds(const gfx::RectF& target_bounds,
                              OverviewAnimationType animation_type) {
   if (in_bounds_update_ ||
-      !Shell::Get()->overview_controller()->InOverviewSession())
+      !Shell::Get()->overview_controller()->InOverviewSession()) {
     return;
+  }
 
   // Do not animate if the resulting bounds does not change. The original
   // window may change bounds so we still need to call SetItemBounds to update
@@ -398,6 +399,8 @@ void OverviewItem::SetBounds(const gfx::RectF& target_bounds,
     SetItemBounds(inset_bounds, new_animation_type, is_first_update);
     UpdateHeaderLayout(is_first_update ? OVERVIEW_ANIMATION_NONE
                                        : new_animation_type);
+    if (is_first_update && !should_animate_when_entering_)
+      transform_window_.ClipHeaderIfNeeded(/*animate=*/false);
   }
 
   // Shadow is normally set after an animation is finished. In the case of no
@@ -760,9 +763,7 @@ void OverviewItem::UpdateRoundedCornersAndShadow() {
     overview_item_view_->UpdatePreviewRoundedCorners(
         should_show_rounded_corners);
   } else {
-    transform_window_.UpdateRoundedCorners(
-        should_show_rounded_corners,
-        /*update_clip=*/should_show_rounded_corners);
+    transform_window_.UpdateRoundedCornersAndClip(should_show_rounded_corners);
   }
 
   // In addition, the shadow should be hidden if

ash/wm/overview/scoped_overview_transform_window.cc

@@ -148,11 +148,10 @@ ScopedOverviewTransformWindow::~ScopedOverviewTransformWindow() {
     event_targeting_blocker_map_.erase(transient);
   }
 
-  // No need to update the clip since we're about to restore it to
-  // `original_clip_rect_`.
-  UpdateRoundedCorners(/*show=*/false, /*update_clip=*/false);
-  aura::client::GetTransientWindowClient()->RemoveObserver(this);
+  // Remove rounded corners and clipping.
+  UpdateRoundedCornersAndClip(/*show=*/false);
   window_->layer()->SetClipRect(original_clip_rect_);
+  aura::client::GetTransientWindowClient()->RemoveObserver(this);
 }
 
 // static
@@ -396,8 +395,7 @@ void ScopedOverviewTransformWindow::UpdateWindowDimensionsType() {
   type_ = GetWindowDimensionsType(window_->bounds().size());
 }
 
-void ScopedOverviewTransformWindow::UpdateRoundedCorners(bool show,
-                                                         bool update_clip) {
+void ScopedOverviewTransformWindow::UpdateRoundedCornersAndClip(bool show) {
   // Hide the corners if minimized, OverviewItemView will handle showing the
   // rounded corners on the UI.
   const bool show_corners = show && !IsMinimized();
@@ -411,21 +409,38 @@ void ScopedOverviewTransformWindow::UpdateRoundedCorners(bool show,
   layer->SetRoundedCornerRadius(radii);
   layer->SetIsFastRoundedCorner(true);
 
-  if (!update_clip || layer->GetAnimator()->is_animating() || IsMinimized())
+  if (!show || layer->GetAnimator()->is_animating() || IsMinimized())
     return;
 
+  ClipHeaderIfNeeded(true);
+}
+
+void ScopedOverviewTransformWindow::ClipHeaderIfNeeded(bool animate) {
   const int top_inset = GetTopInset();
-  if (!has_aspect_ratio_clipping_ && top_inset > 0) {
-    gfx::Rect clip_rect(window_->bounds().size());
-    // We add 1 to the top_inset, because in some cases, the header is not
-    // clipped fully due to what seems to be a rounding error.
-    // TODO(afakhry|sammiequon): Investigate a proper fix for this.
-    clip_rect.Inset(0, top_inset + 1, 0, 0);
-    ScopedOverviewAnimationSettings settings(
+  if (top_inset <= 0)
+    return;
+
+  // Clipping a window to preserve aspect ratios will account for the header, so
+  // no need to clip here.
+  if (has_aspect_ratio_clipping_)
+    return;
+
+  gfx::Rect clip_rect(window_->bounds().size());
+  // We add 1 to the top_inset, because in some cases, the header is not
+  // clipped fully due to what seems to be a rounding error.
+  // TODO(afakhry|sammiequon): Investigate a proper fix for this.
+  clip_rect.Inset(0, top_inset + 1, 0, 0);
+
+  if (overview_clip_rect_ == clip_rect)
+    return;
+
+  std::unique_ptr<ScopedOverviewAnimationSettings> settings;
+  if (animate) {
+    settings = std::make_unique<ScopedOverviewAnimationSettings>(
         OVERVIEW_ANIMATION_FRAME_HEADER_CLIP, window_);
-    layer->SetClipRect(clip_rect);
-    overview_clip_rect_ = clip_rect;
   }
+  window_->layer()->SetClipRect(clip_rect);
+  overview_clip_rect_ = clip_rect;
 }
 
 void ScopedOverviewTransformWindow::OnTransientChildWindowAdded(

ash/wm/overview/scoped_overview_transform_window.h

@@ -123,11 +123,14 @@ class ASH_EXPORT ScopedOverviewTransformWindow
   // change. Must be called before PositionWindows in OverviewGrid.
   void UpdateWindowDimensionsType();
 
-  // Updates the rounded corners on the window. Makes the rounded corners if
-  // |show| is true, otherwise removes it. If |update_clip| is true, it will
-  // clip the top portion of the window that normally contains the caption (if
-  // any), otherwise it will skip updating that clip.
-  void UpdateRoundedCorners(bool show, bool update_clip);
+  // Updates the rounded corners and clipping on the window. Note that the
+  // rounded corners can be hidden with |show| set to false, but the clipping
+  // stays for the duration of overview once applied.
+  void UpdateRoundedCornersAndClip(bool show);
+
+  // Clip the top portion of the window that normally contains the caption (if
+  // any).
+  void ClipHeaderIfNeeded(bool animate);
 
   // aura::client::TransientWindowClientObserver:
   void OnTransientChildWindowAdded(aura::Window* parent,