Remove deprecated StringBuffer.add, addAll and addCharCode.

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 61 matching lines @@
       ClassElement enclosingClass = element.getEnclosingClass();
 
       if (element.isInstanceMember()
           && enclosingClass.isNative()
           && native.isOverriddenMethod(
               element, enclosingClass, nativeEmitter)) {
         // Record that this method is overridden. In case of optional
         // arguments, the emitter will generate stubs to handle them,
         // and needs to know if the method is overridden.
         nativeEmitter.overriddenMethods.add(element);
-        StringBuffer buffer = new StringBuffer();
-        body =
-            nativeEmitter.generateMethodBodyWithPrototypeCheckForElement(
-                element, codegen.body, codegen.parameters);
+        body = nativeEmitter.generateMethodBodyWithPrototypeCheckForElement(
+                  element, codegen.body, codegen.parameters);
       } else {
         body = codegen.body;
       }
 
       return buildJavaScriptFunction(element, codegen.parameters, body);
     });
   }
 
   js.Expression generateBailoutMethod(CodegenWorkItem work, HGraph graph) {
     return measure(() {
@@ skipping 2869 matching lines @@
   if (leftType.canBeNull() && rightType.canBeNull()) {
     if (left.isConstantNull() || right.isConstantNull() ||
         (leftType.isPrimitive() && leftType == rightType)) {
       return '==';
     }
     return null;
   } else {
     return '===';
   }
 }