Retain tray bubble's rounded corners when the bubble animates out

by transferring ownership of a layer mask to the associated layer.

BUG=235563
TEST=Manual: when closing an Ash tray menu or tray notification, watch corners
     to make sure they remain rounded.
R=piman@chromium.org, msw@chromium.org, mukai@chromium.org, skuhne@chromium.org

Review URL: https://codereview.chromium.org/25961002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239930 0039d316-1c4b-4281-b951-d872f2087c98

ui/compositor/layer.cc

@@ -57,8 +57,6 @@ Layer::Layer()
       layer_brightness_(0.0f),
       layer_grayscale_(0.0f),
       layer_inverted_(false),
-      layer_mask_(NULL),
-      layer_mask_back_link_(NULL),
       zoom_(1),
       zoom_inset_(0),
       delegate_(NULL),
@@ -81,8 +79,6 @@ Layer::Layer(LayerType type)
       layer_brightness_(0.0f),
       layer_grayscale_(0.0f),
       layer_inverted_(false),
-      layer_mask_(NULL),
-      layer_mask_back_link_(NULL),
       zoom_(1),
       zoom_inset_(0),
       delegate_(NULL),
@@ -101,12 +97,10 @@ Layer::~Layer() {
   animator_ = NULL;
   if (compositor_)
     compositor_->SetRootLayer(NULL);
+  if (layer_mask_.get())
+    SetMaskLayer(scoped_ptr<Layer>());
   if (parent_)
     parent_->Remove(this);
-  if (layer_mask_)
-    SetMaskLayer(NULL);
-  if (layer_mask_back_link_)
-    layer_mask_back_link_->SetMaskLayer(NULL);
   for (size_t i = 0; i < children_.size(); ++i)
     children_[i]->parent_ = NULL;
   cc_layer_->RemoveLayerAnimationEventObserver(this);
@@ -281,28 +275,18 @@ void Layer::SetLayerInverted(bool inverted) {
   SetLayerFilters();
 }
 
-void Layer::SetMaskLayer(Layer* layer_mask) {
+void Layer::SetMaskLayer(scoped_ptr<Layer> layer_mask) {
   // The provided mask should not have a layer mask itself.
-  DCHECK(!layer_mask ||
+  DCHECK(!layer_mask.get() ||
          (!layer_mask->layer_mask_layer() &&
-          layer_mask->children().empty() &&
-          !layer_mask->layer_mask_back_link_));
-  DCHECK(!layer_mask_back_link_);
-  if (layer_mask_ == layer_mask)
+          layer_mask->children().empty()));
+  if (layer_mask_.get() == layer_mask.get())
     return;
-  // We need to de-reference the currently linked object so that no problem
-  // arises if the mask layer gets deleted before this object.
-  if (layer_mask_)
-    layer_mask_->layer_mask_back_link_ = NULL;
-  layer_mask_ = layer_mask;
+  layer_mask_ = layer_mask.Pass();
   cc_layer_->SetMaskLayer(
-      layer_mask ? layer_mask->cc_layer() : NULL);
-  // We need to reference the linked object so that it can properly break the
-  // link to us when it gets deleted.
-  if (layer_mask) {
-    layer_mask->layer_mask_back_link_ = this;
-    layer_mask->OnDeviceScaleFactorChanged(device_scale_factor_);
-  }
+      layer_mask_.get() ? layer_mask_->cc_layer() : NULL);
+  if (layer_mask_.get())
+    layer_mask_->OnDeviceScaleFactorChanged(device_scale_factor_);
 }
 
 void Layer::SetBackgroundZoom(float zoom, int inset) {

ui/compositor/layer.h

@@ -198,11 +198,10 @@ class COMPOSITOR_EXPORT Layer
 
   // Set a layer mask for a layer.
   // Note the provided layer mask can neither have a layer mask itself nor can
-  // it have any children. The ownership of |layer_mask| will not be
-  // transferred with this call.
+  // it have any children.
   // Furthermore: A mask layer can only be set to one layer.
-  void SetMaskLayer(Layer* layer_mask);
-  Layer* layer_mask_layer() { return layer_mask_; }
+  void SetMaskLayer(scoped_ptr<Layer> layer_mask);
+  Layer* layer_mask_layer() { return layer_mask_.get(); }
 
   // Sets the visibility of the Layer. A Layer may be visible but not
   // drawn. This happens if any ancestor of a Layer is not visible.
@@ -449,12 +448,8 @@ class COMPOSITOR_EXPORT Layer
   float layer_grayscale_;
   bool layer_inverted_;
 
-  // The associated mask layer with this layer.
-  Layer* layer_mask_;
-  // The back link from the mask layer to it's associated masked layer.
-  // We keep this reference for the case that if the mask layer gets deleted
-  // while attached to the main layer before the main layer is deleted.
-  Layer* layer_mask_back_link_;
+  // The mask layer associated with this layer.
+  scoped_ptr<Layer> layer_mask_;
 
   // The zoom factor to scale the layer by.  Zooming is disabled when this is
   // set to 1.

ui/views/bubble/tray_bubble_view.cc

@@ -179,7 +179,7 @@ class TrayBubbleContentMask : public ui::LayerDelegate {
   explicit TrayBubbleContentMask(int corner_radius);
   virtual ~TrayBubbleContentMask();
 
-  ui::Layer* layer() { return &layer_; }
+  void set_bounds(gfx::Rect bounds) { bounds_ = bounds; }
 
   // Overridden from LayerDelegate.
   virtual void OnPaintLayer(gfx::Canvas* canvas) OVERRIDE;
@@ -187,25 +187,22 @@ class TrayBubbleContentMask : public ui::LayerDelegate {
   virtual base::Closure PrepareForLayerBoundsChange() OVERRIDE;
 
  private:
-  ui::Layer layer_;
+  gfx::Rect bounds_;
   SkScalar corner_radius_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayBubbleContentMask);
 };
 
 TrayBubbleContentMask::TrayBubbleContentMask(int corner_radius)
-    : layer_(ui::LAYER_TEXTURED),
-      corner_radius_(corner_radius) {
-  layer_.set_delegate(this);
+    : corner_radius_(corner_radius) {
 }
 
 TrayBubbleContentMask::~TrayBubbleContentMask() {
-  layer_.set_delegate(NULL);
 }
 
 void TrayBubbleContentMask::OnPaintLayer(gfx::Canvas* canvas) {
   SkPath path;
-  path.addRoundRect(gfx::RectToSkRect(gfx::Rect(layer()->bounds().size())),
+  path.addRoundRect(gfx::RectToSkRect(gfx::Rect(bounds_.size())),
                     corner_radius_, corner_radius_);
   SkPaint paint;
   paint.setAlpha(255);
@@ -340,6 +337,10 @@ TrayBubbleView::TrayBubbleView(gfx::NativeView parent_window,
 
 TrayBubbleView::~TrayBubbleView() {
   mouse_watcher_.reset();
+
+  if (layer()->parent()->layer_mask_layer())
+    layer()->parent()->layer_mask_layer()->set_delegate(NULL);
+
   // Inform host items (models) that their views are being destroyed.
   if (delegate_)
     delegate_->BubbleViewDestroyed();
@@ -350,8 +351,11 @@ void TrayBubbleView::InitializeAndShowBubble() {
   SetAlignment(params_.arrow_alignment);
   bubble_border_->UpdateArrowOffset();
 
-  if (get_use_acceleration_when_possible())
-    layer()->parent()->SetMaskLayer(bubble_content_mask_->layer());
+  if (get_use_acceleration_when_possible()) {
+    scoped_ptr<ui::Layer> mask_layer(new ui::Layer(ui::LAYER_TEXTURED));
+    mask_layer->set_delegate(bubble_content_mask_.get());
+    layer()->parent()->SetMaskLayer(mask_layer.Pass());
+  }
 
   GetWidget()->Show();
   UpdateBubble();
@@ -359,8 +363,11 @@ void TrayBubbleView::InitializeAndShowBubble() {
 
 void TrayBubbleView::UpdateBubble() {
   SizeToContents();
-  if (get_use_acceleration_when_possible())
-    bubble_content_mask_->layer()->SetBounds(layer()->bounds());
+  if (get_use_acceleration_when_possible()) {
+    bubble_content_mask_->set_bounds(layer()->bounds());
+    if (layer()->parent()->layer_mask_layer())
+      layer()->parent()->layer_mask_layer()->SetBounds(layer()->bounds());
+  }
   GetWidget()->GetRootView()->SchedulePaint();
 }