Move LayerImpl's bounds_delta to property trees

cc/layers/layer_impl.cc

Index: cc/layers/layer_impl.cc
diff --git a/cc/layers/layer_impl.cc b/cc/layers/layer_impl.cc
index ea79a82eda68aa97735c5f61fe7e944ba7773a77..c17873affbb22815e0bbe7aab721831034c7594c 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -382,7 +382,7 @@ gfx::Vector2dF LayerImpl::FixedContainerSizeDelta() const {
   if (!scroll_clip_layer)
     return gfx::Vector2dF();
 
-  return scroll_clip_layer->bounds_delta();
+  return scroll_clip_layer->ViewportBoundsDelta();
 }
 
 std::unique_ptr<base::DictionaryValue> LayerImpl::LayerTreeAsJson() {
@@ -506,14 +506,15 @@ bool LayerImpl::IsActive() const {
 }
 
 gfx::Size LayerImpl::bounds() const {
-  gfx::Vector2d delta = gfx::ToCeiledVector2d(bounds_delta_);
-  return gfx::Size(bounds_.width() + delta.x(),
-                   bounds_.height() + delta.y());
+  auto viewport_bounds_delta = gfx::ToCeiledVector2d(ViewportBoundsDelta());
+  return gfx::Size(bounds_.width() + viewport_bounds_delta.x(),
+                   bounds_.height() + viewport_bounds_delta.y());
 }
 
 gfx::SizeF LayerImpl::BoundsForScrolling() const {
-  return gfx::SizeF(bounds_.width() + bounds_delta_.x(),
-                    bounds_.height() + bounds_delta_.y());
+  auto viewport_bounds_delta = ViewportBoundsDelta();
+  return gfx::SizeF(bounds_.width() + viewport_bounds_delta.x(),
+                    bounds_.height() + viewport_bounds_delta.y());
 }
 
 void LayerImpl::SetBounds(const gfx::Size& bounds) {
@@ -527,12 +528,11 @@ void LayerImpl::SetBounds(const gfx::Size& bounds) {
   NoteLayerPropertyChanged();
 }
 
-void LayerImpl::SetBoundsDelta(const gfx::Vector2dF& bounds_delta) {
+void LayerImpl::SetViewportBoundsDelta(const gfx::Vector2dF& bounds_delta) {
   DCHECK(IsActive());
-  if (bounds_delta_ == bounds_delta)
-    return;
 
-  bounds_delta_ = bounds_delta;
+  if (bounds_delta == ViewportBoundsDelta())

[enne (OOO), 2017/04/24 18:05:08]

This is premature optimization, but I think this check is redundant.  You have
to do a series of conditionals to get this value, so might as well just do a
series of conditionals and try to set it and then the set function can early out
if needed (which they do).

[pdr., 2017/04/24 20:06:49]

I wanted to preserve the behavior that DidUpdateScrollState is not called unless
the value really changes. I agree that this could be optimized further though.

+    return;
 
   PropertyTrees* property_trees = GetPropertyTrees();
   if (this == layer_tree_impl()->InnerViewportContainerLayer())
@@ -541,6 +541,8 @@ void LayerImpl::SetBoundsDelta(const gfx::Vector2dF& bounds_delta) {
     property_trees->SetOuterViewportContainerBoundsDelta(bounds_delta);
   else if (this == layer_tree_impl()->InnerViewportScrollLayer())
     property_trees->SetInnerViewportScrollBoundsDelta(bounds_delta);
+  else
+    DCHECK(false);

[ajuma, 2017/04/24 17:37:09]

NOTREACHED()

[pdr., 2017/04/24 20:06:49]

Done

 
   layer_tree_impl()->DidUpdateScrollState(id());
 
@@ -560,6 +562,16 @@ void LayerImpl::SetBoundsDelta(const gfx::Vector2dF& bounds_delta) {
   }
 }
 
+gfx::Vector2dF LayerImpl::ViewportBoundsDelta() const {
+  if (this == layer_tree_impl()->InnerViewportContainerLayer())
+    return GetPropertyTrees()->inner_viewport_container_bounds_delta();
+  else if (this == layer_tree_impl()->OuterViewportContainerLayer())
+    return GetPropertyTrees()->outer_viewport_container_bounds_delta();
+  else if (this == layer_tree_impl()->InnerViewportScrollLayer())
+    return GetPropertyTrees()->inner_viewport_scroll_bounds_delta();
+  return gfx::Vector2dF();
+}
+
 ScrollbarLayerImplBase* LayerImpl::ToScrollbarLayer() {
   return nullptr;
 }