Support extracting source mapping url defined by //@ sourceMappingURL=<url> comment.

test/mjsunit/debug-compile-event.js

Index: test/mjsunit/debug-compile-event.js
diff --git a/test/mjsunit/debug-compile-event.js b/test/mjsunit/debug-compile-event.js
index b00a907a3cf79f4d1316fff559751f479549febc..581ad41b91267071a84ab3fd8adba9d1ab624263 100644
--- a/test/mjsunit/debug-compile-event.js
+++ b/test/mjsunit/debug-compile-event.js
@@ -81,9 +81,15 @@ function listener(event, exec_state, event_data, data) {
       assertTrue('context' in msg.body.script);
 
       // Check that we pick script name from //@ sourceURL, iff present
-      assertEquals(current_source.indexOf('sourceURL') >= 0 ? 
+      assertEquals(current_source.indexOf('sourceURL') >= 0 ?
                      'myscript.js' : undefined,
                    event_data.script().name());
+
+      // Check that we pick source mapping url from //@ sourceMappingURL, if
+      // present.
+      assertEquals(current_source.indexOf('sourceMappingURL') >= 0 ?
+                     'http://example.com/sourceMapping.json' : undefined,
+                   event_data.script().sourceMappingURL());
     }
   } catch (e) {
     exception = e
@@ -103,7 +109,8 @@ compileSource('eval("eval(\'(function(){return a;})\')")');
 source_count += 2;  // Using eval causes additional compilation event.
 compileSource('JSON.parse(\'{"a":1,"b":2}\')');
 // Using JSON.parse does not causes additional compilation events.
-compileSource('x=1; //@ sourceURL=myscript.js');
+compileSource('x=1; //@ sourceURL=myscript.js\n' +
+              '//@ sourceMappingURL=http://example.com/sourceMapping.json');
 
 // Make sure that the debug event listener was invoked.
 assertFalse(exception, "exception in listener")