gn: handle continued suffix comments

tools/gn/tokenizer.cc

Index: tools/gn/tokenizer.cc
diff --git a/tools/gn/tokenizer.cc b/tools/gn/tokenizer.cc
index ea7c55ab8b95ea10892bcb39d672ea7e5c844961..318a310a4db4cd37e05c34c93c9dfe8822881408 100644
--- a/tools/gn/tokenizer.cc
+++ b/tools/gn/tokenizer.cc
@@ -128,10 +128,17 @@ std::vector<Token> Tokenizer::Run() {
       std::string trimmed;
       // TODO(scottmg): Should write TrimWhitespace for StringPiece.
       base::TrimWhitespace(to_newline.as_string(), base::TRIM_ALL, &trimmed);
-      if (trimmed.empty())
+      if (trimmed.empty() &&
+          // If it's a standalone comment, but is a continuation of a comment
+          // on a previous line, then instead make it a continued suffix
+          // comment.
+          (tokens_.empty() || tokens_.back().type() != Token::SUFFIX_COMMENT ||
+           tokens_.back().location().line_number() + 1 !=
+               location.line_number())) {
         type = Token::LINE_COMMENT;
-      else
+      } else {
         type = Token::SUFFIX_COMMENT;
+      }
     }
 
     tokens_.push_back(Token(location, type, token_value));