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

ui/compositor/layer.cc

 // Copyright (c) 2012 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 "ui/compositor/layer.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 38 matching lines @@
       parent_(NULL),
       visible_(true),
       force_render_surface_(false),
       fills_bounds_opaquely_(true),
       layer_updated_externally_(false),
       background_blur_radius_(0),
       layer_saturation_(0.0f),
       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),
       cc_layer_(NULL),
       scale_content_(true),
       device_scale_factor_(1.0f) {
   CreateWebLayer();
 }
 
 Layer::Layer(LayerType type)
     : type_(type),
       compositor_(NULL),
       parent_(NULL),
       visible_(true),
       force_render_surface_(false),
       fills_bounds_opaquely_(true),
       layer_updated_externally_(false),
       background_blur_radius_(0),
       layer_saturation_(0.0f),
       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),
       cc_layer_(NULL),
       scale_content_(true),
       device_scale_factor_(1.0f) {
   CreateWebLayer();
 }
 
 Layer::~Layer() {
   // Destroying the animator may cause observers to use the layer (and
   // indirectly the WebLayer). Destroy the animator first so that the WebLayer
   // is still around.
   if (animator_.get())
     animator_->SetDelegate(NULL);
   animator_ = NULL;
   if (compositor_)
     compositor_->SetRootLayer(NULL);
   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;
+  if (layer_mask_.get())
+    cc_layer_->SetMaskLayer(NULL);

[michaelpg, 2013/10/04 05:56:41]

in lieu of calling SetMaskLayer with an empty scoped_ptr<Layer>

   cc_layer_->RemoveLayerAnimationEventObserver(this);
   cc_layer_->RemoveFromParent();
 }
 
 Compositor* Layer::GetCompositor() {
   return GetRoot(this)->compositor_;
 }
 
 float Layer::opacity() const {
   return cc_layer_->opacity();
@@ skipping 152 matching lines @@
     return animator_->GetTargetGrayscale();
   }
   return layer_grayscale();
 }
 
 void Layer::SetLayerInverted(bool inverted) {
   layer_inverted_ = 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)
-    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->children().empty()));
+
   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.get() ? layer_mask->cc_layer() : NULL);
+
+  if (layer_mask)
     layer_mask->OnDeviceScaleFactorChanged(device_scale_factor_);
-  }
+
+  layer_mask_.reset(layer_mask.release());

[michaelpg, 2013/10/04 05:56:41]

layer_mask is a scoped_ptr that now owns the layer, so we have to transfer that
ownership to the layer_mask_ member variable... is there a cleaner way to do
this?

If not, should I use layer_mask.Pass() instead of release()? Digging through
scoped_ptr and move.h seems to indicate that this will ultimately call swap()
thus transferring ownership to layer_mask_.

[piman, 2013/10/04 18:05:33]

Yes, layer_mask_ = layer_mask.Pass(); is more idiomatic.

[michaelpg, 2013/12/10 02:04:03]

Ok, thanks.

 }
 
 void Layer::SetBackgroundZoom(float zoom, int inset) {
   zoom_ = zoom;
   zoom_inset_ = inset;
 
   SetLayerBackgroundFilters();
 }
 
 void Layer::SetLayerFilters() {
@@ skipping 301 matching lines @@
   gfx::Transform transform = this->transform();
   device_scale_factor_ = device_scale_factor;
   RecomputeCCTransformFromTransform(transform);
   RecomputeDrawsContentAndUVRect();
   RecomputePosition();
   SchedulePaint(gfx::Rect(bounds_.size()));
   if (delegate_)
     delegate_->OnDeviceScaleFactorChanged(device_scale_factor);
   for (size_t i = 0; i < children_.size(); ++i)
     children_[i]->OnDeviceScaleFactorChanged(device_scale_factor);
-  if (layer_mask_)
+  if (layer_mask_.get())
     layer_mask_->OnDeviceScaleFactorChanged(device_scale_factor);
 }
 
 void Layer::RequestCopyOfOutput(scoped_ptr<cc::CopyOutputRequest> request) {
   cc_layer_->RequestCopyOfOutput(request.Pass());
 }
 
 void Layer::PaintContents(SkCanvas* sk_canvas,
                           gfx::Rect clip,
                           gfx::RectF* opaque) {
@@ skipping 335 matching lines @@
   cc_layer_->SetBounds(ConvertSizeToPixel(this, size));
 }
 
 void Layer::RecomputePosition() {
   cc_layer_->SetPosition(gfx::ScalePoint(
         gfx::PointF(bounds_.x(), bounds_.y()),
         device_scale_factor_));
 }
 
 }  // namespace ui