Revert r23380, some browser tests fail.

sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart

Index: sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart
===================================================================
--- sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart	(revision 23381)
+++ sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart	(working copy)
@@ -58,6 +58,7 @@
   bool needsInheritFunction = false;
   bool needsDefineClass = false;
   bool needsMixinSupport = false;
+  bool needsClosureClass = false;
   bool needsLazyInitializer = false;
   final Namer namer;
   ConstantEmitter constantEmitter;
@@ -93,6 +94,13 @@
   final Map<int, String> boundClosureCache;
 
   /**
+   * A cache of closures that are used to closurize instance methods
+   * of interceptors. These closures are dynamically bound to the
+   * interceptor instance, and the actual receiver of the method.
+   */
+  final Map<int, String> interceptorClosureCache;
+
+  /**
    * Raw ClassElement symbols occuring in is-checks and type assertions.  If the
    * program contains parameterized checks `x is Set<int>` and
    * `x is Set<String>` then the ClassElement `Set` will occur once in
@@ -125,6 +133,7 @@
       : mainBuffer = new CodeBuffer(),
         this.namer = namer,
         boundClosureCache = new Map<int, String>(),
+        interceptorClosureCache = new Map<int, String>(),
         constantEmitter = new ConstantEmitter(compiler, namer),
         super(compiler) {
     nativeEmitter = new NativeEmitter(this);
@@ -1747,6 +1756,19 @@
     return (ClassElement cls) => !unneededClasses.contains(cls);
   }
 
+  void emitClosureClassIfNeeded(CodeBuffer buffer) {
+    // The closure class could have become necessary because of the generation
+    // of stubs.
+    ClassElement closureClass = compiler.closureClass;
+    if (needsClosureClass && !instantiatedClasses.contains(closureClass)) {
+      ClassElement objectClass = compiler.objectClass;
+      if (!instantiatedClasses.contains(objectClass)) {
+        generateClass(objectClass, bufferForElement(objectClass, buffer));
+      }
+      generateClass(closureClass, bufferForElement(closureClass, buffer));
+    }
+  }
+
   void emitFinishClassesInvocationIfNecessary(CodeBuffer buffer) {
     if (needsDefineClass) {
       buffer.write('$finishClassesName($classesCollector,'
@@ -1830,10 +1852,10 @@
         compiler.codegenWorld.staticFunctionsNeedingGetter;
     for (FunctionElement element in
              Elements.sortedByPosition(functionsNeedingGetter)) {
-      assert(instantiatedClasses.contains(compiler.closureClass));
       String staticName = namer.getName(element);
       String superName = namer.getName(compiler.closureClass);
       String name = 'Closure\$${element.name.slowToString()}';
+      needsClosureClass = true;
 
       ClassElement closureClassElement = new ClosureClassElement(
           null, new SourceString(name), compiler, element,
@@ -1892,7 +1914,6 @@
    */
   void emitDynamicFunctionGetter(FunctionElement member,
                                  DefineStubFunction defineStub) {
-    assert(instantiatedClasses.contains(compiler.boundClosureClass));
     assert(invariant(member, member.isDeclaration));
     // For every method that has the same name as a property-get we create a
     // getter that returns a bound closure. Say we have a class 'A' with method
@@ -1903,9 +1924,10 @@
     //    foo(x, y, z) { ... } // Original function.
     //    get foo { return new BoundClosure499(this, "foo"); }
     // }
-    // class BoundClosure499 extends BoundClosure {
-    //   BoundClosure499(this.self, this.target);
-    //   $call3(x, y, z) { return self[target](x, y, z); }
+    // class BoundClosure499 extends Closure {
+    //   var self;
+    //   BoundClosure499(this.self, this.name);
+    //   $call3(x, y, z) { return self[name](x, y, z); }
     // }
 
     // TODO(floitsch): share the closure classes with other classes
@@ -1917,14 +1939,22 @@
     bool hasOptionalParameters = member.optionalParameterCount(compiler) != 0;
     int parameterCount = member.parameterCount(compiler);
 
-    Map<int, String> cache = boundClosureCache;
+    Map<int, String> cache;
+    String extraArg = null;
     // Intercepted methods take an extra parameter, which is the
     // receiver of the call.
     bool inInterceptor = backend.isInterceptedMethod(member);
-    List<String> fieldNames = <String>[];
-    compiler.boundClosureClass.forEachInstanceField((_, field) {
-      fieldNames.add(namer.getName(field));
-    });
+    if (inInterceptor) {
+      cache = interceptorClosureCache;
+      extraArg = 'receiver';
+    } else {
+      cache = boundClosureCache;
+    }
+    List<String> fieldNames = compiler.enableMinification
+        ? inInterceptor ? const ['a', 'b', 'c']
+                        : const ['a', 'b']
+        : inInterceptor ? const ['self', 'target', 'receiver']
+                        : const ['self', 'target'];
 
     Iterable<Element> typedefChecks =
         getTypedefChecksOn(member.computeType(compiler));
@@ -1938,7 +1968,11 @@
       // Create a new closure class.
       String name;
       if (canBeShared) {
-        name = 'BoundClosure\$${parameterCount}';
+        if (inInterceptor) {
+          name = 'BoundClosure\$i${parameterCount}';
+        } else {
+          name = 'BoundClosure\$${parameterCount}';
+        }
       } else {
         name = 'Bound_${member.name.slowToString()}'
             '_${member.enclosingElement.name.slowToString()}';
@@ -1949,6 +1983,7 @@
           member.getCompilationUnit());
       String mangledName = namer.getName(closureClassElement);
       String superName = namer.getName(closureClassElement.superclass);
+      needsClosureClass = true;
 
       // Define the constructor with a name so that Object.toString can
       // find the class name of the closure class.
@@ -2009,8 +2044,8 @@
     arguments.add(js('this'));
     arguments.add(js.string(targetName));
     if (inInterceptor) {
-      parameters.add('receiver');
-      arguments.add(js('receiver'));
+      parameters.add(extraArg);
+      arguments.add(js(extraArg));
     }
 
     jsAst.Expression getterFunction = js.fun(
@@ -2962,6 +2997,7 @@
       }
 
       emitStaticFunctionClosures();
+      emitClosureClassIfNeeded(mainBuffer);
 
       addComment('Bound closures', mainBuffer);
       // Now that we have emitted all classes, we know all the bound