Use scoped_refptr<const Type> in a few CSS*InterpolationTypes

These instances of StylePath/BasicShape/ShadowList are supposed to be
immutable, so add const qualifications and drop some then unnecessary
const_cast<>s.

Change-Id: I1a6ca8ec9c45dac757a45882129f91f745745023
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2460894Reviewed-by: Robert Flack <flackr@chromium.org>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#815210}

third_party/blink/renderer/core/animation/css_basic_shape_interpolation_type.cc

@@ -68,7 +68,7 @@ class InheritedShapeChecker
     : public CSSInterpolationType::CSSConversionChecker {
  public:
   InheritedShapeChecker(const CSSProperty& property,
-                        scoped_refptr<BasicShape> inherited_shape)
+                        scoped_refptr<const BasicShape> inherited_shape)
       : property_(property), inherited_shape_(std::move(inherited_shape)) {}
 
  private:
@@ -79,7 +79,7 @@ class InheritedShapeChecker
   }
 
   const CSSProperty& property_;
-  scoped_refptr<BasicShape> inherited_shape_;
+  scoped_refptr<const BasicShape> inherited_shape_;
 };
 
 }  // namespace
@@ -110,9 +110,8 @@ InterpolationValue CSSBasicShapeInterpolationType::MaybeConvertInherit(
     const StyleResolverState& state,
     ConversionCheckers& conversion_checkers) const {
   const BasicShape* shape = GetBasicShape(CssProperty(), *state.ParentStyle());
-  // const_cast to take a ref.
-  conversion_checkers.push_back(std::make_unique<InheritedShapeChecker>(
-      CssProperty(), const_cast<BasicShape*>(shape)));
+  conversion_checkers.push_back(
+      std::make_unique<InheritedShapeChecker>(CssProperty(), shape));
   return basic_shape_interpolation_functions::MaybeConvertBasicShape(
       shape, state.ParentStyle()->EffectiveZoom());
 }

third_party/blink/renderer/core/animation/css_path_interpolation_type.cc

@@ -19,7 +19,8 @@ namespace {
 
 // Returns the property's path() value.
 // If the property's value is not a path(), returns nullptr.
-StylePath* GetPath(const CSSProperty& property, const ComputedStyle& style) {
+const StylePath* GetPath(const CSSProperty& property,
+                         const ComputedStyle& style) {
   switch (property.PropertyID()) {
     case CSSPropertyID::kD:
       return style.SvgStyle().D();
@@ -95,7 +96,7 @@ InterpolationValue CSSPathInterpolationType::MaybeConvertInitial(
 class InheritedPathChecker : public CSSInterpolationType::CSSConversionChecker {
  public:
   InheritedPathChecker(const CSSProperty& property,
-                       scoped_refptr<StylePath> style_path)
+                       scoped_refptr<const StylePath> style_path)
       : property_(property), style_path_(std::move(style_path)) {}
 
  private:
@@ -105,7 +106,7 @@ class InheritedPathChecker : public CSSInterpolationType::CSSConversionChecker {
   }
 
   const CSSProperty& property_;
-  const scoped_refptr<StylePath> style_path_;
+  const scoped_refptr<const StylePath> style_path_;
 };
 
 InterpolationValue CSSPathInterpolationType::MaybeConvertInherit(

third_party/blink/renderer/core/animation/css_shadow_list_interpolation_type.cc

@@ -69,7 +69,7 @@ class InheritedShadowListChecker
     : public CSSInterpolationType::CSSConversionChecker {
  public:
   InheritedShadowListChecker(const CSSProperty& property,
-                             scoped_refptr<ShadowList> shadow_list)
+                             scoped_refptr<const ShadowList> shadow_list)
       : property_(property), shadow_list_(std::move(shadow_list)) {}
 
  private:
@@ -85,7 +85,7 @@ class InheritedShadowListChecker
   }
 
   const CSSProperty& property_;
-  scoped_refptr<ShadowList> shadow_list_;
+  scoped_refptr<const ShadowList> shadow_list_;
 };
 
 InterpolationValue CSSShadowListInterpolationType::MaybeConvertInherit(
@@ -96,8 +96,7 @@ InterpolationValue CSSShadowListInterpolationType::MaybeConvertInherit(
   const ShadowList* inherited_shadow_list =
       GetShadowList(CssProperty(), *state.ParentStyle());
   conversion_checkers.push_back(std::make_unique<InheritedShadowListChecker>(
-      CssProperty(),
-      const_cast<ShadowList*>(inherited_shadow_list)));  // Take ref.
+      CssProperty(), inherited_shadow_list));  // Take ref.
   return ConvertShadowList(inherited_shadow_list,
                            state.ParentStyle()->EffectiveZoom());
 }