Round corners of ARC++ notifications during scroll

We have to set insets to ARC++ notification mask so that visible rect
should have appropriate rounded corners during scroll.
Ideally this can be fixed by changing layer ordering of NativeViewHost,
but it's not going to happen soon.

TEST=manual
BUG=866777

Change-Id: Ic4a2dc3c7f56051937dd02ae34fa0ab3bb290c08
Reviewed-on: https://chromium-review.googlesource.com/1215507Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Commit-Queue: Tetsui Ohkubo <tetsui@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590216}

ash/system/message_center/arc/arc_notification_content_view.cc

@@ -346,7 +346,7 @@ void ArcNotificationContentView::UpdateCornerRadius(int top_radius,
   bottom_radius_ = bottom_radius;
 
   if (GetWidget())
-    InstallMask();
+    UpdateMask();
 }
 
 void ArcNotificationContentView::OnSlideChanged() {
@@ -484,7 +484,7 @@ void ArcNotificationContentView::AttachSurface() {
   // (Re-)create the floating buttons after |surface_| is attached to a widget.
   MaybeCreateFloatingControlButtons();
 
-  InstallMask();
+  UpdateMask();
 }
 
 void ArcNotificationContentView::ShowCopiedSurface() {
@@ -522,18 +522,28 @@ void ArcNotificationContentView::HideCopiedSurface() {
 
   // Re-install the mask since the custom mask is unset by
   // |::wm::RecreateLayers()| in |ShowCopiedSurface()| method.
-  InstallMask();
+  UpdateMask();
 }
 
-void ArcNotificationContentView::InstallMask() {
+void ArcNotificationContentView::UpdateMask() {
   if (top_radius_ == 0 && bottom_radius_ == 0) {
     SetCustomMask(nullptr);
+    mask_insets_.reset();
     return;
   }
 
-  SetCustomMask(views::Painter::CreatePaintedLayer(
+  gfx::Insets new_insets = GetContentsBounds().InsetsFrom(GetVisibleBounds());
+  if (mask_insets_ == new_insets)
+    return;
+  mask_insets_ = new_insets;
+
+  auto mask_painter =
       std::make_unique<message_center::NotificationBackgroundPainter>(
-          top_radius_, bottom_radius_)));
+          top_radius_, bottom_radius_);
+  // Set insets to round visible notification corners. https://crbug.com/866777
+  mask_painter->set_insets(new_insets);
+
+  SetCustomMask(views::Painter::CreatePaintedLayer(std::move(mask_painter)));
 }
 
 void ArcNotificationContentView::AddedToWidget() {
@@ -595,6 +605,9 @@ void ArcNotificationContentView::Layout() {
     // |views::NativeViewHostAura::ShowWidget()| and |aura::Window::Show()|
     // which has DCHECK the opacity of the window.
     views::NativeViewHost::Layout();
+    // Reinstall mask to update rounded mask insets. Set null mask unless radius
+    // is set.
+    UpdateMask();
 
     // Scale notification surface if necessary.
     gfx::Transform transform;

ash/system/message_center/arc/arc_notification_content_view.h

@@ -90,7 +90,7 @@ class ArcNotificationContentView
   void HideCopiedSurface();
 
   // Generates a mask using |top_radius_| and |bottom_radius_| and installs it.
-  void InstallMask();
+  void UpdateMask();
 
   // views::NativeViewHost
   void ViewHierarchyChanged(
@@ -175,10 +175,13 @@ class ArcNotificationContentView
 
   base::string16 accessible_name_;
 
-  // Radiuses of rounded corners. These values are used in InstallMask().
+  // Radiuses of rounded corners. These values are used in UpdateMask().
   int top_radius_ = 0;
   int bottom_radius_ = 0;
 
+  // Current insets of mask layer.
+  base::Optional<gfx::Insets> mask_insets_;
+
   std::unique_ptr<ui::LayerTreeOwner> surface_copy_;
   std::unique_ptr<ui::LayerOwner> surface_copy_mask_;
 

ui/message_center/views/notification_background_painter.cc

@@ -31,7 +31,9 @@ void NotificationBackgroundPainter::Paint(gfx::Canvas* canvas,
   SkScalar radii[8] = {top_radius_,    top_radius_,    top_radius_,
                        top_radius_,    bottom_radius_, bottom_radius_,
                        bottom_radius_, bottom_radius_};
-  path.addRoundRect(gfx::RectToSkRect(gfx::Rect(size)), radii);
+  gfx::Rect rect(size);
+  rect.Inset(insets_);
+  path.addRoundRect(gfx::RectToSkRect(rect), radii);
 
   cc::PaintFlags flags;
   flags.setAntiAlias(true);

ui/message_center/views/notification_background_painter.h

@@ -26,11 +26,15 @@ class MESSAGE_CENTER_EXPORT NotificationBackgroundPainter
   gfx::Size GetMinimumSize() const override;
   void Paint(gfx::Canvas* canvas, const gfx::Size& size) override;
 
+  void set_insets(const gfx::Insets& insets) { insets_ = insets; }
+
  private:
   const SkScalar top_radius_;
   const SkScalar bottom_radius_;
   const SkColor color_;
 
+  gfx::Insets insets_;
+
   DISALLOW_COPY_AND_ASSIGN(NotificationBackgroundPainter);
 };