Support animating <resolution> custom properties

third_party/WebKit/Source/core/animation/CSSResolutionInterpolationType.cpp

Index: third_party/WebKit/Source/core/animation/CSSResolutionInterpolationType.cpp
diff --git a/third_party/WebKit/Source/core/animation/CSSResolutionInterpolationType.cpp b/third_party/WebKit/Source/core/animation/CSSResolutionInterpolationType.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..4dd92818739b3aa2569208be19731d468b35acd6
--- /dev/null
+++ b/third_party/WebKit/Source/core/animation/CSSResolutionInterpolationType.cpp
@@ -0,0 +1,37 @@
+// 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.
+
+#include "core/animation/CSSResolutionInterpolationType.h"
+
+#include "core/css/CSSPrimitiveValue.h"
+
+namespace blink {
+
+InterpolationValue CSSResolutionInterpolationType::MaybeConvertNeutral(
+    const InterpolationValue&,
+    ConversionCheckers&) const {
+  return InterpolationValue(InterpolableNumber::Create(0));
+}
+
+InterpolationValue CSSResolutionInterpolationType::MaybeConvertValue(
+    const CSSValue& value,
+    const StyleResolverState*,
+    ConversionCheckers&) const {
+  if (!value.IsPrimitiveValue() ||
+      !CSSPrimitiveValue::IsResolution(
+          ToCSSPrimitiveValue(value).TypeWithCalcResolved()))
+    return nullptr;
+  return InterpolationValue(InterpolableNumber::Create(
+      ToCSSPrimitiveValue(value).ComputeDotsPerPixel()));
+}
+
+const CSSValue* CSSResolutionInterpolationType::CreateCSSValue(
+    const InterpolableValue& value,
+    const NonInterpolableValue*,
+    const StyleResolverState&) const {
+  return CSSPrimitiveValue::Create(ToInterpolableNumber(value).Value(),
+                                   CSSPrimitiveValue::UnitType::kDotsPerPixel);
+}
+
+}  // namespace blink