Reland of Changed CSSParserContext argument from * to & for null safety.

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

Index: third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
diff --git a/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp b/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
index fc9cd344d825c5cbdb9e86fe2b5d34352f04abd6..6c69b7b8f9aaae883549777b95066489caec9323 100644
--- a/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
+++ b/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
@@ -1836,8 +1836,10 @@
   // statement.
   const CSSPropertyDescriptor& cssPropertyDesc =
       CSSPropertyDescriptor::get(property);
-  if (cssPropertyDesc.parseSingleValue)
-    return cssPropertyDesc.parseSingleValue(m_range, m_context);
+  if (cssPropertyDesc.parseSingleValue) {
+    DCHECK(m_context);
+    return cssPropertyDesc.parseSingleValue(m_range, *m_context);
+  }
 
   switch (property) {
     case CSSPropertyFontFeatureSettings: