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

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 764cdd909f4842f8ff60e36e2945da5a56079724..0ac50e54dc53f42de07243aa912e7295d59f7cd7 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -6898,6 +6898,12 @@ class Script: public Struct {
   // [flags]: Holds an exciting bitfield.
   DECL_ACCESSORS(flags, Smi)
 
+  // [source_url]: sourceURL from magic comment
+  DECL_ACCESSORS(source_url, Object)
+
+  // [source_url]: sourceMappingURL magic comment
+  DECL_ACCESSORS(source_mapping_url, Object)
+
   // [compilation_type]: how the the script was compiled. Encoded in the
   // 'flags' field.
   inline CompilationType compilation_type();
@@ -6954,7 +6960,9 @@ class Script: public Struct {
       kEvalFromSharedOffset + kPointerSize;
   static const int kFlagsOffset =
       kEvalFrominstructionsOffsetOffset + kPointerSize;
-  static const int kSize = kFlagsOffset + kPointerSize;
+  static const int kSourceUrlOffset = kFlagsOffset + kPointerSize;
+  static const int kSourceMappingUrlOffset = kSourceUrlOffset + kPointerSize;
+  static const int kSize = kSourceMappingUrlOffset + kPointerSize;
 
  private:
   int GetLineNumberWithArray(int code_pos);