Generalize layer mirroring for phantom windows

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 <memory>
 #include <utility>
 
@@ skipping 31 matching lines @@
 const ui::Layer* GetRoot(const ui::Layer* layer) {
   while (layer->parent())
     layer = layer->parent();
   return layer;
 }
 
 }  // namespace
 
 namespace ui {
 
+class Layer::LayerMirror : public LayerDelegate, LayerObserver {
+ public:
+  LayerMirror(Layer* mirrored, Layer* mirror)

[danakj, 2016/10/24 20:28:02]

nit: mirror_source and mirror_dest? or just source and dest?

[Dominik Laskowski, 2016/10/24 22:58:04]

Done.

+      : mirrored_(mirrored), mirror_(mirror) {
+    mirror->AddObserver(this);
+    mirror->set_delegate(this);
+  }
+
+  ~LayerMirror() override {
+    mirror_->RemoveObserver(this);
+    mirror_->set_delegate(nullptr);
+  }
+
+  Layer* layer() { return mirror_; }

[danakj, 2016/10/24 20:28:02]

This method's name is ambiguous can it specify its the source/dest layer in the
relationship?

[Dominik Laskowski, 2016/10/24 22:58:05]

Done.

+
+  // LayerDelegate:
+  void OnPaintLayer(const PaintContext& context) override {
+    if (const auto delegate = mirrored_->delegate())

[danakj, 2016/10/24 20:28:02]

auto*

[Dominik Laskowski, 2016/10/24 22:58:05]

OnPaintLayer isn't const.

[Dominik Laskowski, 2016/10/24 23:15:07]

...or did you mean:

if (auto* delegate = ...

[danakj, 2016/10/24 23:57:57]

That'd be fine yes. It's a raw pointer so denote it with a *

[Dominik Laskowski, 2016/10/25 22:44:56]

Done.

+      delegate->OnPaintLayer(context);
+  }
+  void OnDelegatedFrameDamage(const gfx::Rect& damage_rect_in_dip) override {}
+  void OnDeviceScaleFactorChanged(float device_scale_factor) override {}
+
+  // LayerObserver:
+  void LayerDestroyed(Layer* mirror) override {
+    DCHECK_EQ(mirror_, mirror);
+    mirrored_->OnMirrorDestroyed(this);
+  }
+
+ private:
+  Layer* const mirrored_;
+  Layer* const mirror_;
+
+  DISALLOW_COPY_AND_ASSIGN(LayerMirror);
+};
+
 Layer::Layer()
     : type_(LAYER_TEXTURED),
       compositor_(NULL),
       parent_(NULL),
       visible_(true),
       fills_bounds_opaquely_(true),
       fills_bounds_completely_(false),
       background_blur_radius_(0),
       layer_saturation_(0.0f),
       layer_brightness_(0.0f),
@@ skipping 50 matching lines @@
   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_->RemoveFromParent();
   if (mailbox_release_callback_)
     mailbox_release_callback_->Run(gpu::SyncToken(), false);
 }
 
+std::unique_ptr<Layer> Layer::Clone() const {
+  auto clone = base::MakeUnique<Layer>(type_);
+
+  clone->SetTransform(GetTargetTransform());
+  clone->SetBounds(bounds_);
+  clone->SetSubpixelPositionOffset(subpixel_position_offset_);
+  clone->SetMasksToBounds(GetMasksToBounds());
+  clone->SetOpacity(GetTargetOpacity());
+  clone->SetVisible(GetTargetVisibility());
+  clone->SetFillsBoundsOpaquely(fills_bounds_opaquely_);
+  clone->SetFillsBoundsCompletely(fills_bounds_completely_);
+  clone->set_name(name_);
+
+  // Background filters.
+  clone->SetBackgroundBlur(background_blur_radius_);
+  clone->SetBackgroundZoom(zoom_, zoom_inset_);
+
+  // Filters.
+  clone->SetLayerSaturation(layer_saturation_);
+  clone->SetLayerBrightness(GetTargetBrightness());
+  clone->SetLayerGrayscale(GetTargetGrayscale());
+  clone->SetLayerInverted(layer_inverted_);
+  if (alpha_shape_)
+    clone->SetAlphaShape(base::MakeUnique<SkRegion>(*alpha_shape_));
+
+  // cc::Layer state.
+  if (surface_layer_ && !surface_layer_->surface_id().is_null()) {
+    clone->SetShowSurface(
+        surface_layer_->surface_id(),
+        surface_layer_->satisfy_callback(),
+        surface_layer_->require_callback(),
+        surface_layer_->surface_size(),
+        surface_layer_->surface_scale(),
+        frame_size_in_dip_);
+  } else if (type_ == LAYER_SOLID_COLOR) {
+    clone->SetColor(GetTargetColor());
+  }
+  return clone;
+}
+
 const Compositor* Layer::GetCompositor() const {
   return GetRoot(this)->compositor_;
 }
 
 float Layer::opacity() const {
   return cc_layer_->opacity();
 }
 
 void Layer::SetCompositor(Compositor* compositor,
                           scoped_refptr<cc::Layer> root_layer) {
@@ skipping 454 matching lines @@
 
   scoped_refptr<cc::SurfaceLayer> new_layer =
       cc::SurfaceLayer::Create(satisfy_callback, require_callback);
   new_layer->SetSurfaceId(surface_id, scale, surface_size);
   SwitchToLayer(new_layer);
   surface_layer_ = new_layer;
 
   frame_size_in_dip_ = frame_size_in_dip;
   RecomputeDrawsContentAndUVRect();
 
-  for (auto& observer : observer_list_)
-    observer.SurfaceChanged(this);
+  for (const auto& mirror : mirrors_) {
+    mirror->layer()->SetShowSurface(
+        surface_id, satisfy_callback, require_callback,
+        surface_size, scale, frame_size_in_dip);
+  }
+}
+
+std::unique_ptr<Layer> Layer::Mirror() {
+  auto mirror = Clone();
+  mirrors_.emplace_back(base::MakeUnique<LayerMirror>(this, mirror.get()));
+  return mirror;
 }
 
 void Layer::SetShowSolidColorContent() {
   DCHECK_EQ(type_, LAYER_SOLID_COLOR);
 
   if (solid_color_layer_.get())
     return;
 
   scoped_refptr<cc::SolidColorLayer> new_layer = cc::SolidColorLayer::Create();
   SwitchToLayer(new_layer);
@@ skipping 36 matching lines @@
   nine_patch_layer_->SetBorder(border);
 }
 
 void Layer::UpdateNinePatchOcclusion(const gfx::Rect& occlusion) {
   DCHECK(type_ == LAYER_NINE_PATCH && nine_patch_layer_.get());
   nine_patch_layer_->SetLayerOcclusion(occlusion);
 }
 
 void Layer::SetColor(SkColor color) { GetAnimator()->SetColor(color); }
 
-SkColor Layer::GetTargetColor() {
-  if (GetAnimator()->IsAnimatingProperty(LayerAnimationElement::COLOR))
-    return GetAnimator()->GetTargetColor();
+SkColor Layer::GetTargetColor() const {
+  if (animator_.get() && animator_->IsAnimatingProperty(

[danakj, 2016/10/24 20:28:02]

no .get() needed

[Dominik Laskowski, 2016/10/24 22:58:04]

Done, and elsewhere too.

+      LayerAnimationElement::COLOR))
+    return animator_->GetTargetColor();
   return cc_layer_->background_color();
 }
 
 SkColor Layer::background_color() const {
   return cc_layer_->background_color();
 }
 
 bool Layer::SchedulePaint(const gfx::Rect& invalid_rect) {
   if ((type_ == LAYER_SOLID_COLOR && !texture_layer_.get()) ||
       type_ == LAYER_NINE_PATCH || (!delegate_ && !mailbox_.IsValid()))
@@ skipping 123 matching lines @@
   paint_region_.Clear();
   cc::DisplayItemListSettings settings;
   settings.use_cached_picture = false;
   scoped_refptr<cc::DisplayItemList> display_list =
       cc::DisplayItemList::Create(settings);
   if (delegate_) {
     delegate_->OnPaintLayer(
         PaintContext(display_list.get(), device_scale_factor_, invalidation));
   }
   display_list->Finalize();
-  for (auto& observer : observer_list_)
-    observer.DidPaintLayer(this, invalidation);
+  for (const auto& mirror : mirrors_)
+    mirror->layer()->SchedulePaint(invalidation);

[danakj, 2016/10/24 20:28:02]

I would expect SchedulePaint for the whole layers bounds when Mirror() happens,
and then propogate SchedulePaint() calls from SchedulePaint(), and do nothing
here. Would that work?

[Dominik Laskowski, 2016/10/24 22:58:04]

I was also wondering why DidPaintLayer was called here and not from
SchedulePaint, but it's not a trivial refactoring so I'd rather not attempt it
in this CL.

[danakj, 2016/10/24 23:57:57]

Would you mind leaving a TODO describing this all then? And maybe file and point
it at a bug?

[Dominik Laskowski, 2016/10/25 22:44:56]

Done, but a bug seems overkill.

   return display_list;
 }
 
 bool Layer::FillsBoundsCompletely() const { return fills_bounds_completely_; }
 
 size_t Layer::GetApproximateUnsharedMemoryUsage() const {
   // Most of the "picture memory" is shared with the cc::DisplayItemList, so
   // there's nothing significant to report here.
   return 0;
 }
@@ skipping 97 matching lines @@
 
   if (bounds.size() == old_bounds.size()) {
     // Don't schedule a draw if we're invisible. We'll schedule one
     // automatically when we get visible.
     if (IsDrawn())
       ScheduleDraw();
   } else {
     // Always schedule a paint, even if we're invisible.
     SchedulePaint(gfx::Rect(bounds.size()));
   }
+
+  if (sync_bounds_) {
+    for (const auto& mirror : mirrors_)
+      mirror->layer()->SetBounds(bounds);
+  }
 }
 
 void Layer::SetTransformFromAnimation(const gfx::Transform& transform) {
   cc_layer_->SetTransform(transform);
 }
 
 void Layer::SetOpacityFromAnimation(float opacity) {
   cc_layer_->SetOpacity(opacity);
   ScheduleDraw();
 }
@@ skipping 140 matching lines @@
 
   if (animator_) {
     animator_->DetachLayerAndTimeline(compositor);
     animator_->RemoveFromCollection(collection);
   }
 
   for (auto* child : children_)
     child->ResetCompositorForAnimatorsInTree(compositor);
 }
 
+void Layer::OnMirrorDestroyed(LayerMirror* mirror) {
+  const auto it = std::find_if(mirrors_.begin(), mirrors_.end(),
+      [mirror](const std::unique_ptr<LayerMirror>& mirror_ptr) {
+        return mirror_ptr.get() == mirror;
+      });
+
+  DCHECK(it != mirrors_.end());
+  mirrors_.erase(it);
+}
+
 }  // namespace ui