dart2js cps: Generate increment and compound operators.

pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart

Index: pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart
diff --git a/pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart b/pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart
index 215cf3ae74021c00eb6d418bf3115a24631acb35..eaa24e961fdbd4483df98ecb56327d46c23e950c 100644
--- a/pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart
+++ b/pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart
@@ -743,7 +743,11 @@ class SetField extends Expression {
   Element field;
   Expression value;
 
-  SetField(this.object, this.field, this.value);
+  /// If non-null, this is a compound assignment to the field, using the given
+  /// operator.  The operator must be a compoundable operator.
+  BuiltinOperator compound;
+
+  SetField(this.object, this.field, this.value, {this.compound});
 
   accept(ExpressionVisitor visitor) => visitor.visitSetField(this);
   accept1(ExpressionVisitor1 visitor, arg) => visitor.visitSetField(this, arg);
@@ -813,8 +817,9 @@ class SetIndex extends Expression {
   Expression object;
   Expression index;
   Expression value;
+  BuiltinOperator compound;
 
-  SetIndex(this.object, this.index, this.value);
+  SetIndex(this.object, this.index, this.value, {this.compound});
 
   accept(ExpressionVisitor v) => v.visitSetIndex(this);
   accept1(ExpressionVisitor1 v, arg) => v.visitSetIndex(this, arg);