dart2js: Implement frequency based naming.

pkg/compiler/lib/src/js_backend/minify_namer.dart

Index: pkg/compiler/lib/src/js_backend/minify_namer.dart
diff --git a/pkg/compiler/lib/src/js_backend/minify_namer.dart b/pkg/compiler/lib/src/js_backend/minify_namer.dart
index 9a2d1e3fc4a1290eb5a086a1cceeaae5933d20fe..b6801684b7a65aac77cd1e0808819e968a3ce39b 100644
--- a/pkg/compiler/lib/src/js_backend/minify_namer.dart
+++ b/pkg/compiler/lib/src/js_backend/minify_namer.dart
@@ -7,7 +7,8 @@ part of js_backend;
 /**
  * Assigns JavaScript identifiers to Dart variables, class-names and members.
  */
-class MinifyNamer extends Namer with _MinifiedFieldNamer {
+class MinifyNamer extends Namer with _MinifiedFieldNamer,
+    _MinifiedOneShotInterceptorNamer {
   MinifyNamer(Compiler compiler) : super(compiler) {
     reserveBackendNames();
     fieldRegistry = new _FieldNamingRegistry(this);
@@ -32,11 +33,11 @@ class MinifyNamer extends Namer with _MinifiedFieldNamer {
   /// [sanitizeForNatives] and [sanitizeForAnnotations] are ignored because the
   /// minified names will always avoid clashing with annotated names or natives.
   @override
-  jsAst.Name getFreshName(String proposedName,
-                          Set<String> usedNames,
-                          Map<String, String> suggestedNames,
-                          {bool sanitizeForNatives: false,
-                           bool sanitizeForAnnotations: false}) {
+  String _generateFreshStringForName(String proposedName,
+      Set<String> usedNames,
+      Map<String, String> suggestedNames,
+      {bool sanitizeForNatives: false,
+       bool sanitizeForAnnotations: false}) {
     String freshName;
     String suggestion = suggestedNames[proposedName];
     if (suggestion != null && !usedNames.contains(suggestion)) {
@@ -46,7 +47,7 @@ class MinifyNamer extends Namer with _MinifiedFieldNamer {
           suggestedNames.values);
     }
     usedNames.add(freshName);
-    return new StringBackedName(freshName);
+    return freshName;
   }
 
   // From issue 7554.  These should not be used on objects (as instance
@@ -192,7 +193,7 @@ class MinifyNamer extends Namer with _MinifiedFieldNamer {
 
   /// Instance members starting with g and s are reserved for getters and
   /// setters.
-  bool _hasBannedPrefix(String name) {
+  static bool _hasBannedPrefix(String name) {
     int code = name.codeUnitAt(0);
     return code == $g || code == $s;
   }
@@ -255,3 +256,18 @@ class MinifyNamer extends Namer with _MinifiedFieldNamer {
   }
 }
 
+abstract class _MinifiedOneShotInterceptorNamer implements Namer {
+  /// Property name used for the one-shot interceptor method for the given
+  /// [selector] and return-type specialization.
+  jsAst.Name nameForGetOneShotInterceptor(Selector selector,
+      Iterable<ClassElement> classes) {
+    String root = selector.isOperator ? operatorNameToIdentifier(selector.name)
+    : privateName(selector.memberName);
+    String prefix = selector.isGetter ? r"$get"
+    : selector.isSetter ? r"$set" : "";
+    String arity = selector.isCall ? "${selector.argumentCount}" : "";
+    String suffix = suffixForGetInterceptor(classes);
+    String fullName = "\$intercepted$prefix\$$root$arity\$$suffix";
+    return _disambiguateInternalGlobal(fullName);
+  }
+}