[CSS Grid Layout] Support dots sequences in grid-template-areas

Source/core/css/parser/CSSPropertyParser.cpp

Index: Source/core/css/parser/CSSPropertyParser.cpp
diff --git a/Source/core/css/parser/CSSPropertyParser.cpp b/Source/core/css/parser/CSSPropertyParser.cpp
index 119ea6bf959ffa64c81bf48d7c10d1bf913d9a73..bf84ef6f726aee064349217d260629b100ec4be2 100644
--- a/Source/core/css/parser/CSSPropertyParser.cpp
+++ b/Source/core/css/parser/CSSPropertyParser.cpp
@@ -3613,6 +3613,17 @@ PassRefPtrWillBeRawPtr<CSSPrimitiveValue> CSSPropertyParser::parseGridBreadth(CS
     return createPrimitiveNumericValue(currentValue);
 }
 
+static bool containsOnlyDots(const String& string)
+{
+    ASSERT(!string.isEmpty());
+    StringImpl& text = *string.impl();
+    for (unsigned i = 0; i < text.length(); ++i) {
+        if (text[i] != '.')
+            return false;
+    }
+    return true;
+}
+
 bool CSSPropertyParser::parseGridTemplateAreasRow(NamedGridAreaMap& gridAreaMap, const size_t rowCount, size_t& columnCount)
 {
     CSSParserValue* currentValue = m_valueList->current();
@@ -3638,7 +3649,7 @@ bool CSSPropertyParser::parseGridTemplateAreasRow(NamedGridAreaMap& gridAreaMap,
         const String& gridAreaName = columnNames[currentCol];
 
         // Unamed areas are always valid (we consider them to be 1x1).
-        if (gridAreaName == ".")
+        if (containsOnlyDots(gridAreaName))
             continue;
 
         // We handle several grid areas with the same name at once to simplify the validation code.