dart2js cps_ir: Use interceptors for is-checks.

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 ddaf34ddef5ba9362866db110393ff39be81d8fe..95bc497b11d0ca69c825c3c941a8e32bb2371a4f 100644
--- a/pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart
+++ b/pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart
@@ -742,6 +742,22 @@ class SetField extends Expression {
   accept1(ExpressionVisitor1 visitor, arg) => visitor.visitSetField(this, arg);
 }
 
+
+/// Read the type test property from [object]. The value is truthy/fasly rather
+/// than bool. [object] must not be `null`.
+class GetTypeTestProperty extends Expression {
+  Expression object;
+  DartType dartType;
+
+  GetTypeTestProperty(this.object, this.dartType);
+
+  accept(ExpressionVisitor visitor) =>
+      visitor.visitGetTypeTestProperty(this);
+  accept1(ExpressionVisitor1 visitor, arg) =>
+      visitor.visitGetTypeTestProperty(this, arg);
+}
+
+
 /// Read the value of a field, possibly provoking its initializer to evaluate,
 /// or tear off a static method.
 class GetStatic extends Expression {
@@ -975,6 +991,7 @@ abstract class ExpressionVisitor<E> {
   E visitSetField(SetField node);
   E visitGetStatic(GetStatic node);
   E visitSetStatic(SetStatic node);
+  E visitGetTypeTestProperty(GetTypeTestProperty node);
   E visitCreateBox(CreateBox node);
   E visitCreateInstance(CreateInstance node);
   E visitReifyRuntimeType(ReifyRuntimeType node);
@@ -1012,6 +1029,7 @@ abstract class ExpressionVisitor1<E, A> {
   E visitSetField(SetField node, A arg);
   E visitGetStatic(GetStatic node, A arg);
   E visitSetStatic(SetStatic node, A arg);
+  E visitGetTypeTestProperty(GetTypeTestProperty node, A arg);
   E visitCreateBox(CreateBox node, A arg);
   E visitCreateInstance(CreateInstance node, A arg);
   E visitReifyRuntimeType(ReifyRuntimeType node, A arg);
@@ -1206,6 +1224,10 @@ abstract class RecursiveVisitor implements StatementVisitor, ExpressionVisitor {
     visitExpression(node.value);
   }
 
+  visitGetTypeTestProperty(GetTypeTestProperty node) {
+    visitExpression(node.object);
+  }
+
   visitCreateBox(CreateBox node) {
   }
 
@@ -1451,6 +1473,11 @@ class RecursiveTransformer extends Transformer {
     return node;
   }
 
+  visitGetTypeTestProperty(GetTypeTestProperty node) {
+    node.object = visitExpression(node.object);
+    return node;
+  }
+
   visitCreateBox(CreateBox node) => node;
 
   visitCreateInstance(CreateInstance node) {