Implement parseShorthand API for shorthand properties, "overflow", "font" and "font-variant"

third_party/WebKit/Source/core/css/properties/CSSShorthandPropertyAPIOverflow.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/CSSShorthandPropertyAPIOverflow.h"
+
+#include "core/css/CSSIdentifierValue.h"
+#include "core/css/parser/CSSParserContext.h"
+#include "core/css/parser/CSSParserFastPaths.h"
+#include "core/css/parser/CSSPropertyParserHelpers.h"
+
+namespace blink {
+
+class CSSParserLocalContext;

[Bugs Nash, 2017/06/16 03:51:51]

as above

+
+bool CSSShorthandPropertyAPIOverflow::parseShorthand(
+    bool important,
+    CSSParserTokenRange& range,
+    const CSSParserContext* context,
+    const CSSParserLocalContext&,
+    HeapVector<CSSProperty, 256>& properties) {
+  DCHECK(context);
+
+  CSSValueID id = range.ConsumeIncludingWhitespace().Id();
+  if (!CSSParserFastPaths::IsValidKeywordPropertyAndValue(CSSPropertyOverflowY,
+                                                          id, context->Mode()))
+    return false;
+  if (!range.AtEnd())
+    return false;
+  CSSValue* overflow_y_value = CSSIdentifierValue::Create(id);
+
+  CSSValue* overflow_x_value = nullptr;
+
+  // FIXME: -webkit-paged-x or -webkit-paged-y only apply to overflow-y.
+  // If
+  // this value has been set using the shorthand, then for now overflow-x
+  // will default to auto, but once we implement pagination controls, it
+  // should default to hidden. If the overflow-y value is anything but
+  // paged-x or paged-y, then overflow-x and overflow-y should have the
+  // same
+  // value.
+  if (id == CSSValueWebkitPagedX || id == CSSValueWebkitPagedY)
+    overflow_x_value = CSSIdentifierValue::Create(CSSValueAuto);
+  else
+    overflow_x_value = overflow_y_value;
+  CSSPropertyParserHelpers::AddProperty(
+      CSSPropertyOverflowX, CSSPropertyOverflow, *overflow_x_value, important,
+      false /* implicit */, properties);
+  CSSPropertyParserHelpers::AddProperty(
+      CSSPropertyOverflowY, CSSPropertyOverflow, *overflow_y_value, important,
+      false /* implicit */, properties);
+  return true;
+}
+
+}  // namespace blink