Fix source locations for inlined and patched functions.

lib/compiler/implementation/js_backend/emitter.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /**
  * A function element that represents a closure call. The signature is copied
  * from the given element.
  */
 class ClosureInvocationElement extends FunctionElement {
   ClosureInvocationElement(SourceString name,
@@ skipping 1268 matching lines @@
         // hack.
         compiler.reportDiagnostic(
             null, sourceMap, new api.Diagnostic(-1, 'source map'));
       }
     });
     return compiler.assembledCode;
   }
 
   String buildSourceMap(CodeBuffer buffer, SourceFile compiledFile) {
     SourceMapBuilder sourceMapBuilder = new SourceMapBuilder();
-    buffer.forEachSourceLocation((Element element, Token token, int offset) {
-      if (element == null) {
-        sourceMapBuilder.addMapping(null, null, null, offset);
-        return;
-      }
-      SourceFile sourceFile = element.getCompilationUnit().script.file;
-      String sourceName = null;
-      if (token.kind === IDENTIFIER_TOKEN) {
-        sourceName = token.slowToString();
-      }
-      sourceMapBuilder.addMapping(
-          sourceFile, token.charOffset, sourceName, offset);
-    });
+    buffer.forEachSourceLocation(sourceMapBuilder.addMapping);
     return sourceMapBuilder.build(compiledFile);
   }
 }
 
 typedef void DefineMemberFunction(String invocationName, CodeBuffer definition);