WIP Support var() references in registered custom property keyframes

third_party/WebKit/Source/core/animation/CSSInterpolationEnvironment.h

 // Copyright 2017 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.
 
 #ifndef CSSInterpolationEnvironment_h
 #define CSSInterpolationEnvironment_h
 
 #include "core/animation/InterpolationEnvironment.h"
 #include "core/css/resolver/StyleResolverState.h"
 
 namespace blink {
 
 class ComputedStyle;
+class CSSVariableResolver;
 
 class CSSInterpolationEnvironment : public InterpolationEnvironment {
  public:
-  explicit CSSInterpolationEnvironment(const InterpolationTypesMap& map,
-                                       StyleResolverState& state)
-      : InterpolationEnvironment(map), state_(&state), style_(state.Style()) {}
+  explicit CSSInterpolationEnvironment(
+      const InterpolationTypesMap& map,
+      StyleResolverState& state,
+      CSSVariableResolver* variable_resolver = nullptr)
+      : InterpolationEnvironment(map),
+        state_(&state),
+        style_(state.Style()),
+        variable_resolver_(variable_resolver) {}
 
   explicit CSSInterpolationEnvironment(const InterpolationTypesMap& map,
                                        const ComputedStyle& style)
       : InterpolationEnvironment(map), style_(&style) {}
 
   bool IsCSS() const final { return true; }
 
   StyleResolverState& GetState() {
     DCHECK(state_);
     return *state_;
   }
   const StyleResolverState& GetState() const {
     DCHECK(state_);
     return *state_;
   }
 
   const ComputedStyle& Style() const {
     DCHECK(style_);
     return *style_;
   }
 
+  CSSVariableResolver& VariableResolver() const {
+    DCHECK(variable_resolver_);
+    return *variable_resolver_;
+  }
+
  private:
   StyleResolverState* state_ = nullptr;
   const ComputedStyle* style_ = nullptr;
+  CSSVariableResolver* variable_resolver_ = nullptr;
 };
 
 DEFINE_TYPE_CASTS(CSSInterpolationEnvironment,
                   InterpolationEnvironment,
                   value,
                   value->IsCSS(),
                   value.IsCSS());
 
 }  // namespace blink
 
 #endif  // CSSInterpolationEnvironment_h