Move the dart2js snapshot into bin directory of sdk root.

sdk/lib/_internal/compiler/implementation/dart2js.dart

 // Copyright (c) 2013, 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.
 
 library dart2js;
 
 import 'dart:async';
 import 'dart:collection' show Queue, LinkedHashMap;
 import 'dart:io';
 import 'dart:uri';
 import 'dart:utf';
 
 import '../compiler.dart' as api;
 import 'source_file.dart';
 import 'source_file_provider.dart';
 import 'filenames.dart';
 import 'util/uri_extras.dart';
 import '../../libraries.dart';
 
 const String LIBRARY_ROOT = '../../../../..';
 const String OUTPUT_LANGUAGE_DART = 'Dart';
 
+/**
+ * A string to identify the revision or build.
+ *
+ * This ID is displayed if the compiler crashes and in verbose mode, and is
+ * an aid in reproducing bug reports.
+ *
+ * The actual string is rewritten by a wrapper script when included in the sdk.
+ */
+String BUILD_ID = 'build number could not be determined';
+
+/**
+ * Allows wrapping scripts to explicitly provide the options passed to the
+ * program instead of using the standard dart:io.
+ */
+Options OPTIONS_OVERRIDE = null;
+
 typedef void HandleOption(String option);
 
 class OptionHandler {
   String pattern;
   HandleOption handle;
 
   OptionHandler(this.pattern, this.handle);
 }
 
 /**
@@ skipping 271 matching lines @@
       if (isPrimaryOutput) {
         charactersWritten += sink.count;
       }
     }
 
     var controller = new StreamController<String>();
     controller.stream.listen(output.write, onDone: onDone);
     sink = new CountingSink(controller);
     return sink;
   }
-
+ 
   api.compile(uri, libraryRoot, packageRoot,
               inputProvider.readStringFromUri, handler,
               options, outputProvider)
       .then(compilationDone);
 }
 
 // TODO(ahe): Get rid of this class if http://dartbug.com/8118 is fixed.
 class CountingSink implements EventSink<String> {
   final EventSink<String> sink;
   int count = 0;
@@ skipping 26 matching lines @@
 }
 
 void fail(String message) {
   print(message);
   exit(1);
 }
 
 void compilerMain(Options options) {
   var root = uriPathToNative("/$LIBRARY_ROOT");
   List<String> argv = ['--library-root=${options.script}$root'];
+  if (OPTIONS_OVERRIDE != null) options = OPTIONS_OVERRIDE;
   argv.addAll(options.arguments);
   compile(argv);
 }
 
 void help() {
   // This message should be no longer than 20 lines. The default
   // terminal size normally 80x24. Two lines are used for the prompts
   // before and after running the compiler. Another two lines may be
   // used to print an error message.
   print('''
@@ skipping 124 matching lines @@
     } catch (ignored) {
       print('Internal error: error while printing exception');
     }
     try {
       print(trace);
     } finally {
       exit(253); // 253 is recognized as a crash by our test scripts.
     }
   }
 }