Remove support for >>> and >>>= operators in dartc

compiler/java/com/google/dart/compiler/backend/js/GenerateJavascriptAST.java

Index: compiler/java/com/google/dart/compiler/backend/js/GenerateJavascriptAST.java
diff --git a/compiler/java/com/google/dart/compiler/backend/js/GenerateJavascriptAST.java b/compiler/java/com/google/dart/compiler/backend/js/GenerateJavascriptAST.java
index 94a479721841790dd84a7353bb300fd281a59913..b93d12ed2730b929c8a05f5e18edcf182904f45b 100644
--- a/compiler/java/com/google/dart/compiler/backend/js/GenerateJavascriptAST.java
+++ b/compiler/java/com/google/dart/compiler/backend/js/GenerateJavascriptAST.java
@@ -1,4 +1,4 @@
-// Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file
+// 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.
 
@@ -1062,7 +1062,7 @@ public class GenerateJavascriptAST {
         JsNew jsNew = new JsNew(curClassJsName.makeRef());
         if (classElement.getNativeName() != null && x.getFunction().getBody() == null) {
           /*
-           * For native classes with bodyless constructors, we pass the user-declared arguments of 
+           * For native classes with bodyless constructors, we pass the user-declared arguments of
            * the factory method to the native "new" expression.
            */
           List<JsExpression> newArguments = jsNew.getArguments();
@@ -3402,7 +3402,6 @@ public class GenerateJavascriptAST {
         case ASSIGN_BIT_AND: return JsBinaryOperator.ASG_BIT_AND;
         case ASSIGN_SHL: return JsBinaryOperator.ASG_SHL;
         case ASSIGN_SAR: return JsBinaryOperator.ASG_SHR;
-        case ASSIGN_SHR: return JsBinaryOperator.ASG_SHRU;
         case ASSIGN_ADD: return JsBinaryOperator.ASG_ADD;
         case ASSIGN_SUB: return JsBinaryOperator.ASG_SUB;
         case ASSIGN_MUL: return JsBinaryOperator.ASG_MUL;
@@ -3417,7 +3416,6 @@ public class GenerateJavascriptAST {
         case BIT_AND: return JsBinaryOperator.BIT_AND;
         case SHL: return JsBinaryOperator.SHL;
         case SAR: return JsBinaryOperator.SHR;
-        case SHR: return JsBinaryOperator.SHRU;
         case ADD: return JsBinaryOperator.ADD;
         case SUB: return JsBinaryOperator.SUB;
         case MUL: return JsBinaryOperator.MUL;