dart2js: Implement frequency based naming.

pkg/compiler/lib/src/js_emitter/old_emitter/nsm_emitter.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.
 
 part of dart2js.js_emitter;
 
 class NsmEmitter extends CodeEmitterHelper {
   final List<Selector> trivialNsmHandlers = <Selector>[];
 
   /// If this is true then we can generate the noSuchMethod handlers at startup
@@ skipping 273 matching lines @@
 
     return statements;
   }
 }
 
 /// When pretty printed, this node computes a diff-encoded string for the list
 /// of given names.
 ///
 /// See [buildTrivialNsmHandlers].
 class _DiffEncodedListOfNames extends jsAst.DeferredString
-                              implements AstContainer {
+                              implements jsAst.AstContainer {
   String _cachedValue;
-  jsAst.ArrayInitializer ast;
+  List<jsAst.ArrayInitializer> ast;
+
+  Iterable<jsAst.Node> get containedNodes => ast;
 
   _DiffEncodedListOfNames(Iterable<Iterable<jsAst.Name>> names) {
     // Store the names in ArrayInitializer nodes to make them discoverable
     // by traversals of the ast.
-    ast = new jsAst.ArrayInitializer(
-        names.map((Iterable i) => new jsAst.ArrayInitializer(i.toList()))
-             .toList());
+    ast = names.map((Iterable i) => new jsAst.ArrayInitializer(i.toList()))
+               .toList();
   }
 
   void _computeDiffEncodingForList(Iterable<jsAst.Name> names,
                                    StringBuffer diffEncoding) {
     // Treat string as a number in base 88 with digits in ASCII order from # to
     // z.  The short name sorting is based on length, and uses ASCII order for
     // equal length strings so this means that names are ascending.  The hash
     // character, #, is never given as input, but we need it because it's the
     // implicit leading zero (otherwise we could not code names with leading
     // dollar signs).
@@ skipping 46 matching lines @@
         if (diffEncoding.length != 0) {
           diffEncoding.write(',');
         }
         diffEncoding.write(short);
       }
     }
   }
 
   String _computeDiffEncoding() {
     StringBuffer buffer = new StringBuffer();
-    for (jsAst.ArrayInitializer list in ast.elements) {
+    for (jsAst.ArrayInitializer list in ast) {
       if (buffer.isNotEmpty) {
         // Emit period that resets the diff base to zero when we switch to
         // normal calling convention (this avoids the need to code negative
         // diffs).
         buffer.write(".");
       }
       List<jsAst.Name> names = list.elements;
       _computeDiffEncodingForList(names, buffer);
     }
     return '"${buffer.toString()}"';
   }
 
   String get value {
     if (_cachedValue == null) {
       _cachedValue = _computeDiffEncoding();
     }
 
     return _cachedValue;
   }
 }