Move frog/leg to lib/compiler/implementation.

tests/utils/src/DummyCompilerTest.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.
 
 // Smoke test of the dart2js compiler API.
 
-#import('../../../frog/leg/api.dart');
+#import('../../../lib/compiler/compiler.dart');
 #import('../../../lib/uri/uri.dart');
 
 Future<String> provider(Uri uri) {
   Completer<String> completer = new Completer<String>();
   String source;
   if (uri.scheme == "main") {
     source = "main() {}";
   } else {
     source = "#library('lib');";
   }
   completer.complete(source);
   return completer.future;
 }
 
 void handler(Uri uri, int begin, int end, String message, bool fatal) {
   print(message);
 }
 
 main() {
   String code = compile(new Uri(scheme: 'main'), new Uri(scheme: 'lib'),
                         provider, handler).value;
   if (code === null) {
     throw 'Compilation failed';
   }
 }