blink: Add backdrop-filter support

Source/core/css/resolver/StyleBuilderCustom.cpp

Index: Source/core/css/resolver/StyleBuilderCustom.cpp
diff --git a/Source/core/css/resolver/StyleBuilderCustom.cpp b/Source/core/css/resolver/StyleBuilderCustom.cpp
index ff629ab79e437a58c16a05f4d9d724c6861f07c9..ce14743d725fd949f1e83d3b005c70e026c14681 100644
--- a/Source/core/css/resolver/StyleBuilderCustom.cpp
+++ b/Source/core/css/resolver/StyleBuilderCustom.cpp
@@ -588,6 +588,14 @@ void StyleBuilderFunctions::applyValueCSSPropertyWebkitFilter(StyleResolverState
     state.style()->setFilter(operations);
 }
 
+void StyleBuilderFunctions::applyValueCSSPropertyBackdropFilter(StyleResolverState& state, CSSValue* value)
+{
+    // FIXME: We should just make this a converter
+    FilterOperations operations;
+    FilterOperationResolver::createFilterOperations(*value, state.cssToLengthConversionData(), operations, state);
+    state.style()->setBackdropFilter(operations);
+}
+
 void StyleBuilderFunctions::applyInitialCSSPropertyWebkitTextEmphasisStyle(StyleResolverState& state)
 {
     state.style()->setTextEmphasisFill(ComputedStyle::initialTextEmphasisFill());