dart2js cps: Rewrite more List operations into JS array operations.

pkg/compiler/lib/src/cps_ir/builtin_operator.dart

 // Copyright (c) 2015, 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.
 library builtin_operator;
 // This is shared by the CPS and Tree IRs.
 // Both cps_ir_nodes and tree_ir_nodes import and re-export this file.
 
 /// An operator supported natively in the CPS and Tree IRs using the
 /// `ApplyBuiltinOperator` instructions.
 ///
@@ skipping 86 matching lines @@
   /// Compiles to `Math.floor(x) === x`
   IsFloor,
 
   /// Returns true if the argument is an integer.
   ///
   /// The argument must be repeated 3 times.
   ///
   /// Compiles to `typeof x === 'number' && Math.floor(x) === x`
   IsNumberAndFloor,
 }
+
+/// A method supported natively in the CPS and Tree IRs using the
+/// `ApplyBuiltinMethod` instructions.
+/// 
+/// These methods all operate on a distinguished 'object' argument, and
+/// take zero or more additional arguments.
+/// 
+/// These methods may mutate and depend on the state of the object argument,
+/// but may not depend on or mutate any other state. An exception is thrown
+/// if the object is null, but otherwise they cannot throw or diverge.
+enum BuiltinMethod {
+  /// Add an item to a native list.
+  /// 
+  /// Takes any number of arguments, each argument will be added to the
+  /// list on the order given (as per the JS `push` method).
+  /// 
+  /// Compiles to `object.push(x1, ..., xN)`.
+  Push,
+
+  /// Remove and return the last item from a native list.
+  /// 
+  /// Takes no arguments.
+  /// 
+  /// Compiles to `object.pop()`.
+  Pop,
+}