Start new design for interceptors and implement String.charCodeAt with it.

sdk/lib/_internal/compiler/implementation/ssa/codegen.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.
 
 part of ssa;
 
 class SsaCodeGeneratorTask extends CompilerTask {
 
   final JavaScriptBackend backend;
 
@@ skipping 1502 matching lines @@
     }
   }
 
   js.Call jsPropertyCall(js.Expression receiver,
                          String fieldName,
                          List<js.Expression> arguments) {
     return new js.Call(new js.PropertyAccess.field(receiver, fieldName),
                        arguments);
   }
 
+  // TODO(ngeoffray): Once we remove the old interceptors, we can
+  // start using HInvokeInterceptor to represent interceptor calls on
+  // an Interceptor class. Currently we recognize if a call is a call
+  // on an interceptor by checking if the arguments in the inputs list
+  // is one more than the arguments in the selector. The extra
+  // argument in an interceptor call is the actual receiver.
+  bool isInterceptorCall(HInvokeDynamicMethod node) {
+    return node.inputs.length - 1 != node.selector.argumentCount;
+  }
+
   visitInvokeDynamicMethod(HInvokeDynamicMethod node) {
     use(node.receiver);
     js.Expression object = pop();
     SourceString name = node.selector.name;
     String methodName;
     List<js.Expression> arguments;
     Element target = node.element;
 
     // Avoid adding the generative constructor name to the list of
     // seen selectors.
     if (target != null && target.isGenerativeConstructorBody()) {
       methodName = name.slowToString();
       arguments = visitArguments(node.inputs);
     } else {
       methodName = backend.namer.instanceMethodInvocationName(
           node.selector.library, name, node.selector);
       arguments = visitArguments(node.inputs);
       bool inLoop = node.block.enclosingLoopHeader != null;
 
       // Register this invocation to collect the types used at all call sites.
       Selector selector = getOptimizedSelectorFor(node, node.selector);
-      backend.registerDynamicInvocation(node, selector, types);
+      // TODO(ngeoffray): Remove the following restriction. Because
+      // the second input of this interceptor call is the actual
+      // receiver (the first is the interceptor), the backend gets
+      // confused. We should pass a list of types instead of a node to
+      // [registerDynamicInvocation].
+      if (!isInterceptorCall(node)) {
+        backend.registerDynamicInvocation(node, selector, types);
+      }
 
       // If we don't know what we're calling or if we are calling a getter,
       // we need to register that fact that we may be calling a closure
       // with the same arguments.
       if (target == null || target.isGetter()) {
         // TODO(kasperl): If we have a typed selector for the call, we
         // may know something about the types of closures that need
         // the specific closure call method.
         Selector call = new Selector.callClosureFrom(selector);
         world.registerDynamicInvocation(call.name, call);
@@ skipping 404 matching lines @@
     HInstruction input = node.inputs[0];
     if (input.isConstantNull()) {
       pushStatement(new js.Return(null), node);
     } else {
       use(node.inputs[0]);
       pushStatement(new js.Return(pop()), node);
     }
   }
 
   visitThis(HThis node) {
-    push(new js.This());
+    if (backend.isInterceptorClass(work.element.getEnclosingClass())){
+      push(new js.VariableUse(variableNames.getName(node)), node);
+    } else {
+      push(new js.This());
+    }
   }
 
   visitThrow(HThrow node) {
     if (node.isRethrow) {
       use(node.inputs[0]);
       pushStatement(new js.Throw(pop()), node);
     } else {
       generateThrowWithHelper(r'$throw', node.inputs[0]);
     }
   }
@@ skipping 1100 matching lines @@
   if (leftType.canBeNull() && rightType.canBeNull()) {
     if (left.isConstantNull() || right.isConstantNull() ||
         (leftType.isPrimitive() && leftType == rightType)) {
       return '==';
     }
     return null;
   } else {
     return '===';
   }
 }