First shot at source maps generation in dart2js.

lib/compiler/implementation/apiimpl.dart

Index: lib/compiler/implementation/apiimpl.dart
diff --git a/lib/compiler/implementation/apiimpl.dart b/lib/compiler/implementation/apiimpl.dart
index 709f190b4bea4c7494f4a8bd55b2d671d9b214de..ad8599f0e439bf3bccf6979dcdfee8f2d0e27bd0 100644
--- a/lib/compiler/implementation/apiimpl.dart
+++ b/lib/compiler/implementation/apiimpl.dart
@@ -30,7 +30,9 @@ class Compiler extends leg.Compiler {
           enableTypeAssertions: options.indexOf('--enable-checked-mode') != -1,
           enableUserAssertions: options.indexOf('--enable-checked-mode') != -1,
           emitJavascript: options.indexOf('--output-type=dart') == -1,
-          validateUnparse: options.indexOf('--unparse-validation') !== -1);
+          validateUnparse: options.indexOf('--unparse-validation') !== -1,
+          generateSourceMap: options.some((e) => e.startsWith(

[ahe, 2012/06/20 11:56:59]

As discussed, we don't want to make it a command line option. So this should
just be true.

I think it is nice to keep the bool in the implementation, so it can be turned
off for debugging.

[podivilov, 2012/06/20 14:15:15]

Done.

+              '--source-map-out=')));
 
   elements.LibraryElement scanBuiltinLibrary(String path) {
     Uri uri = libraryRoot.resolve(DART2JS_LIBRARY_MAP[path]);