support function in custom paint input arguments

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

Index: third_party/WebKit/Source/core/css/parser/CSSPropertyParserHelpers.cpp
diff --git a/third_party/WebKit/Source/core/css/parser/CSSPropertyParserHelpers.cpp b/third_party/WebKit/Source/core/css/parser/CSSPropertyParserHelpers.cpp
index ed502005d576616f98a37ef741888b1540a603e0..6ee0e1753a7cb01abd347b17b35bd4c0c6da23d4 100644
--- a/third_party/WebKit/Source/core/css/parser/CSSPropertyParserHelpers.cpp
+++ b/third_party/WebKit/Source/core/css/parser/CSSPropertyParserHelpers.cpp
@@ -1173,7 +1173,19 @@ static CSSValue* consumePaint(CSSParserTokenRange& args,
   Vector<RefPtr<CSSVariableData>> variableData;
   while (!args.atEnd()) {
     if (args.peek().type() != CommaToken) {
-      argumentTokens.push_back(args.consumeIncludingWhitespace());
+      if (args.peek().getBlockType() != CSSParserToken::BlockStart) {

[meade_UTC10, 2017/02/16 02:44:59]

There's a lot of nested ifs in this while loop now. Would it be better to split
this out into two functions? Something like this (incorrect) idea:

while(!args.atEnd()) {
  if (args.peek().getBlockType() != CSSParserToken::BlockStart) {
    // Handle function input
  } else {
    // Handle list input
  }
}

This might make it clearer where the function name is getting parsed - it's not
clear to me now

[renjieliu1, 2017/02/16 04:38:42]

Done.

+        argumentTokens.push_back(args.consumeIncludingWhitespace());
+      } else {
+        // Encounter function block.
+        argumentTokens.push_back(args.peek());

[meade_UTC10, 2017/02/16 02:44:59]

So this pushes an open brace, then the contents of the block, then a closing
brace?

Why not

CSSParserTokenRange contents = args.consumeBlock();
argumentTokens.push_back(LeftBracketToken);
while (!contents.end())
  argumentTokens.push_back(contents.consume()
argumentTokens.push_back(RightBracketToken);

[renjieliu1, 2017/02/16 04:38:42]

I totally agree that's what we should do, however, CSSParserToken treats
function name along with parenthesis as a single token.

Example rgb(1, 2, 3) => rgb(1, 2, 3 after the consumeBlock function.

+        CSSParserTokenRange contents = args.consumeBlock();
+        while (!contents.atEnd()) {
+          argumentTokens.push_back(contents.consume());
+        }
+        // Assume it is a function.

[meade_UTC10, 2017/02/16 02:44:59]

This comment is confusing, suggest removing it.

[renjieliu1, 2017/02/16 04:38:42]

Done.

+        argumentTokens.push_back(
+            CSSParserToken(RightParenthesisToken, CSSParserToken::BlockEnd));
+      }
     } else {
       if (!addCSSPaintArgument(argumentTokens, &variableData))
         return nullptr;