[Typed OM] Add CSSValue -> CSSNumberValue conversion

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

 // This file specifies all the CSS properties we support and the necessary
 // information for our code generation. The various supported arguments
 // are described below with example usage
 
 
 // - alias_for=other-property
 // Properties specifying alias_for should be virtually identical to the
 // properties they alias. Minor parsing differences are allowed as long as
 // the CSSValues created are of the same format of the aliased property.
 
@@ skipping 23 matching lines @@
 
 // - keywords=[keyword1|keyword2]
 // This specifies all valid keyword values for the property.
 // TODO(sashab): Once all properties are represented here, delete
 // CSSValueKeywords.in and use this list instead.
 
 
 // Flags which go into CSSOMTypes:
 // - typedom_types=[Type|OtherType]
 // The property can take types specified in typedom_types for CSS Typed OM.
+// The types available correspond to CSSStyleValue::StyleValueType, with
+// modifications.
+// Integer, PositiveInteger, PositiveNumber, Number => CSSNumberValue with
+// restrictions.
+// Length => expands to CSSLengthValue and subclasses
 // Keyword does not need to be specified as every property can take keywords.
 // - keywords=[keyword1|keyword2]
 // The property can take these keywords.
 // - supports_multiple
 // The property supports a list of values.
 // - supports_percentage
 // The property supports percentage types.
 
 
 // Flags which go into CSSPropertyMetadata:
@@ skipping 61 matching lines @@
 // and writing mode.
 
 
 // Properties with StyleBuilder handling
 
 // Animation Priority properties
 animation-delay custom_all
 animation-direction custom_all
 animation-duration custom_all
 animation-fill-mode custom_all
-animation-iteration-count keywords=[infinite], supports_multiple, custom_all
+animation-iteration-count typedom_types=[PositiveNumber], keywords=[infinite], supports_multiple, custom_all
 animation-name custom_all
 animation-play-state custom_all
 animation-timing-function custom_all
 transition-delay custom_all
 transition-duration custom_all
 transition-property custom_all
 transition-timing-function custom_all
 
 // High Priority and all other font properties.
 // Other properties can depend upon high priority properties (e.g. font-size / ems)
@@ skipping 143 matching lines @@
 motion-offset alias_for=offset-distance
 motion-path alias_for=offset-path
 motion-rotation alias_for=offset-rotation
 object-fit type_name=ObjectFit
 object-position interpolable, converter=convertPosition
 offset-anchor runtime_flag=CSSOffsetPositionAnchor, interpolable, converter=convertPositionOrAuto
 offset-distance interpolable, converter=convertLength
 offset-path converter=convertPathOrNone
 offset-position runtime_flag=CSSOffsetPositionAnchor, interpolable, converter=convertPositionOrAuto
 offset-rotation interpolable, converter=convertOffsetRotation
-opacity interpolable, type_name=float
+opacity interpolable, type_name=float, typedom_types=[Number]
 order type_name=int
 orphans interpolable, inherited, type_name=short
 outline-color interpolable, custom_all
 outline-offset interpolable, converter=convertComputedLength<int>
 outline-style custom_all
 outline-width interpolable, converter=convertLineWidth<unsigned short>
 overflow-anchor runtime_flag=ScrollAnchoring, type_name=EOverflowAnchor
 overflow-wrap inherited
 overflow-x type_name=EOverflow
 overflow-y type_name=EOverflow
@@ skipping 311 matching lines @@
 -webkit-text-size-adjust alias_for=text-size-adjust
 -webkit-transform alias_for=transform
 -webkit-transform-origin alias_for=transform-origin
 -webkit-transform-style alias_for=transform-style
 -webkit-transition alias_for=transition
 -webkit-transition-delay alias_for=transition-delay
 -webkit-transition-duration alias_for=transition-duration
 -webkit-transition-property alias_for=transition-property
 -webkit-transition-timing-function alias_for=transition-timing-function
 -webkit-user-select alias_for=user-select