Handle "//# sourceURL" comments in the Parser instead of the JS.

src/scanner.h

Index: src/scanner.h
diff --git a/src/scanner.h b/src/scanner.h
index 2979082e3f152623527df8a69a4b2d177f592323..5e2e065b3f97c4c702759cb57da996c8ce4abd08 100644
--- a/src/scanner.h
+++ b/src/scanner.h
@@ -450,6 +450,9 @@ class Scanner {
   // be empty).
   bool ScanRegExpFlags();
 
+  bool HasSourceMapComment() { return has_source_map_comment_; }
+  Handle<String> AllocateInternalizedSourceMapComment(Isolate* isolate);
+
  private:
   // The current and look-ahead token.
   struct TokenDesc {
@@ -571,6 +574,7 @@ class Scanner {
 
   bool SkipWhiteSpace();
   Token::Value SkipSingleLineComment();
+  Token::Value SkipSourceMapComment();
   Token::Value SkipMultiLineComment();
   // Scans a possible HTML comment -- begins with '<!'.
   Token::Value ScanHtmlComment();
@@ -605,6 +609,8 @@ class Scanner {
   LiteralBuffer literal_buffer1_;
   LiteralBuffer literal_buffer2_;
 
+  LiteralBuffer source_map_comment_;
+
   TokenDesc current_;  // desc for current token (as returned by Next())
   TokenDesc next_;     // desc for next token (one token look-ahead)
 
@@ -625,6 +631,8 @@ class Scanner {
   // Whether there is a multi-line comment that contains a
   // line-terminator after the current token, and before the next.
   bool has_multiline_comment_before_next_;
+  // Whether the last line we have scanned is a source map comment.
+  bool has_source_map_comment_;
   // Whether we scan 'let' as a keyword for harmony block-scoped let bindings.
   bool harmony_scoping_;
   // Whether we scan 'module', 'import', 'export' as keywords.