Proof of concept that CSSPropertyAPI*::parseSingleValue may need more tahn 2 arguments

third_party/WebKit/Source/core/css/CSSProperties.in

Index: third_party/WebKit/Source/core/css/CSSProperties.in
diff --git a/third_party/WebKit/Source/core/css/CSSProperties.in b/third_party/WebKit/Source/core/css/CSSProperties.in
index 69d78b6c5eebdac23ce5d60f58f06fbdc577e3ca..1037eedbed3715e26952299f378588381f09613b 100644
--- a/third_party/WebKit/Source/core/css/CSSProperties.in
+++ b/third_party/WebKit/Source/core/css/CSSProperties.in
@@ -195,17 +195,17 @@ alignment-baseline svg
 align-self initial=initialSelfAlignment, converter=convertSelfOrDefaultAlignmentData
 backdrop-filter interpolable, converter=convertFilterOperations, runtime_flag=CSSBackdropFilter
 backface-visibility
-background-attachment custom_all
-background-blend-mode custom_all
-background-clip custom_all
+background-attachment custom_all, api_class=CSSPropertyAPIBackgroundComponent
+background-blend-mode custom_all, api_class=CSSPropertyAPIBackgroundComponent
+background-clip custom_all, api_class=CSSPropertyAPIBackgroundComponent
 background-color interpolable, custom_all
-background-image interpolable, custom_all, typedom_types=[Image], keywords=[auto]
-background-origin custom_all
-background-position-x interpolable, custom_all
-background-position-y interpolable, custom_all
+background-image interpolable, custom_all, typedom_types=[Image], keywords=[auto], api_class=CSSPropertyAPIBackgroundComponent
+background-origin custom_all, api_class=CSSPropertyAPIBackgroundComponent
+background-position-x interpolable, custom_all, api_class=CSSPropertyAPIBackgroundComponent
+background-position-y interpolable, custom_all, api_class=CSSPropertyAPIBackgroundComponent
 background-repeat-x custom_all
 background-repeat-y custom_all
-background-size interpolable, custom_all
+background-size interpolable, custom_all, api_class=CSSPropertyAPIBackgroundComponent
 baseline-shift interpolable, svg, custom_inherit, custom_value
 border-bottom-color interpolable, custom_all
 border-bottom-left-radius interpolable, initial=initialBorderRadius, converter=convertRadius, api_class=CSSPropertyAPIBorderRadius
@@ -304,7 +304,7 @@ marker-end inherited, svg, name_for_methods=MarkerEndResource, converter=convert
 marker-mid inherited, svg, name_for_methods=MarkerMidResource, converter=convertFragmentIdentifier
 marker-start inherited, svg, name_for_methods=MarkerStartResource, converter=convertFragmentIdentifier
 mask svg, name_for_methods=MaskerResource, converter=convertFragmentIdentifier
-mask-source-type runtime_flag=CSSMaskSourceType, custom_all
+mask-source-type runtime_flag=CSSMaskSourceType, custom_all, api_class=CSSPropertyAPIBackgroundComponent
 mask-type svg
 max-height interpolable, initial=initialMaxSize, converter=convertLengthMaxSizing
 max-width interpolable, initial=initialMaxSize, converter=convertLengthMaxSizing
@@ -406,8 +406,8 @@ x interpolable, svg, converter=convertLength
 y interpolable, svg, converter=convertLength
 -webkit-appearance type_name=ControlPart
 -webkit-app-region custom_all
--webkit-background-clip use_handlers_for=CSSPropertyBackgroundClip
--webkit-background-origin use_handlers_for=CSSPropertyBackgroundOrigin
+-webkit-background-clip use_handlers_for=CSSPropertyBackgroundClip, api_class=CSSPropertyAPIBackgroundComponent
+-webkit-background-origin use_handlers_for=CSSPropertyBackgroundOrigin, api_class=CSSPropertyAPIBackgroundComponent
 -webkit-border-horizontal-spacing interpolable, inherited, name_for_methods=HorizontalBorderSpacing, converter=convertComputedLength<short>
 -webkit-border-image initial=initialNinePieceImage, custom_value
 -webkit-border-vertical-spacing interpolable, inherited, name_for_methods=VerticalBorderSpacing, converter=convertComputedLength<short>
@@ -441,15 +441,15 @@ column-width interpolable, converter=convertComputedLength<float>, custom_all
 -webkit-mask-box-image-slice interpolable, custom_all
 -webkit-mask-box-image-source interpolable, custom_value
 -webkit-mask-box-image-width interpolable, custom_all
--webkit-mask-clip custom_all
--webkit-mask-composite custom_all
--webkit-mask-image interpolable, custom_all
--webkit-mask-origin custom_all
--webkit-mask-position-x interpolable, custom_all
--webkit-mask-position-y interpolable, custom_all
+-webkit-mask-clip custom_all, api_class=CSSPropertyAPIBackgroundComponent
+-webkit-mask-composite custom_all, api_class=CSSPropertyAPIBackgroundComponent
+-webkit-mask-image interpolable, custom_all, api_class=CSSPropertyAPIBackgroundComponent
+-webkit-mask-origin custom_all, api_class=CSSPropertyAPIBackgroundComponent
+-webkit-mask-position-x interpolable, custom_all, api_class=CSSPropertyAPIBackgroundComponent
+-webkit-mask-position-y interpolable, custom_all, api_class=CSSPropertyAPIBackgroundComponent
 -webkit-mask-repeat-x custom_all
 -webkit-mask-repeat-y custom_all
--webkit-mask-size interpolable, custom_all
+-webkit-mask-size interpolable, custom_all, api_class=CSSPropertyAPIBackgroundComponent
 -webkit-perspective-origin-x interpolable, converter=convertLength
 -webkit-perspective-origin-y interpolable, converter=convertLength
 -webkit-print-color-adjust inherited, independent, keyword_only, keywords=[economy|exact], initial_keyword=economy