Implements CSSPropertyAPI for the flex-basis property.

A part of Project Ribbon, separating the parsing logic for CSS
properties from the parser into an API. This patch removes
CSSPropertyFlexBasis from the switch statement in parseSingleValue,
and calls the API instead.

A function pointer to the parseSingleValue function from the API for the
page property is stored in a CSSPropertyDescriptor, and is called from
CSSPropertyParser.

This patch:
- Adds CSSPropertyAPIFlexBasis.cpp to the BUILD.gn file.
- Adds api_class flag to CSSProperties.in, which indicates that
  CSSPropertyAPIFlexBasis.h is generated.
- Moves the parsing logic for page from CSSPropertyParser.cpp to
  CSSPropertyAPIFlexBasis.cpp, which implements CSSPropertyAPI.h.

BUG=668012

Review-Url: https://codereview.chromium.org/2613843002
Cr-Commit-Position: refs/heads/master@{#442815}

third_party/WebKit/Source/core/css/BUILD.gn

@@ -347,6 +347,7 @@ blink_core_sources("css") {
     "properties/CSSPropertyAPICaretColor.cpp",
     "properties/CSSPropertyAPIClip.cpp",
     "properties/CSSPropertyAPIColumnGap.cpp",
+    "properties/CSSPropertyAPIFlexBasis.cpp",
     "properties/CSSPropertyAPIFontSizeAdjust.cpp",
     "properties/CSSPropertyAPISize.cpp",
     "properties/CSSPropertyAPITextDecorationColor.cpp",

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

@@ -256,7 +256,7 @@ fill interpolable, inherited, svg, setter=setFillPaint, custom_all
 fill-opacity interpolable, inherited, svg, converter=convertNumberOrPercentage
 fill-rule inherited, svg, type_name=WindRule
 filter interpolable, converter=convertFilterOperations
-flex-basis interpolable, converter=convertLengthOrAuto
+flex-basis interpolable, converter=convertLengthOrAuto, api_class
 flex-direction
 flex-grow interpolable, type_name=float
 flex-shrink interpolable, type_name=float

third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp

@@ -1872,14 +1872,6 @@ static CSSValue* consumeNoneOrURI(CSSParserTokenRange& range) {
   return consumeUrl(range);
 }
 
-static CSSValue* consumeFlexBasis(CSSParserTokenRange& range,
-                                  CSSParserMode cssParserMode) {
-  // FIXME: Support intrinsic dimensions too.
-  if (range.peek().id() == CSSValueAuto)
-    return consumeIdent(range);
-  return consumeLengthOrPercent(range, cssParserMode, ValueRangeNonNegative);
-}
-
 static CSSValue* consumeStrokeDasharray(CSSParserTokenRange& range) {
   CSSValueID id = range.peek().id();
   if (id == CSSValueNone)
@@ -3534,8 +3526,6 @@ const CSSValue* CSSPropertyParser::parseSingleValue(
     case CSSPropertyMarkerEnd:
     case CSSPropertyMask:
       return consumeNoneOrURI(m_range);
-    case CSSPropertyFlexBasis:
-      return consumeFlexBasis(m_range, m_context.mode());
     case CSSPropertyFlexGrow:
     case CSSPropertyFlexShrink:
       return consumeNumber(m_range, ValueRangeNonNegative);

third_party/WebKit/Source/core/css/properties/CSSPropertyAPIFlexBasis.cpp

+// 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/css/properties/CSSPropertyAPIFlexBasis.h"
+
+#include "core/css/parser/CSSParserContext.h"
+#include "core/css/parser/CSSPropertyParserHelpers.h"
+
+namespace blink {
+
+const CSSValue* CSSPropertyAPIFlexBasis::parseSingleValue(
+    CSSParserTokenRange& range,
+    const CSSParserContext& context) {
+  // FIXME: Support intrinsic dimensions too.
+  if (range.peek().id() == CSSValueAuto)
+    return CSSPropertyParserHelpers::consumeIdent(range);
+  return CSSPropertyParserHelpers::consumeLengthOrPercent(
+      range, context.mode(), ValueRangeNonNegative);
+}
+
+}  // namespace blink