Implement cascaded calls.

lib/compiler/implementation/ssa/builder.dart

Index: lib/compiler/implementation/ssa/builder.dart
diff --git a/lib/compiler/implementation/ssa/builder.dart b/lib/compiler/implementation/ssa/builder.dart
index 0f48c2db6630722f804d14577f59830eeb5c0b69..112df65c8a10ccde804c4ee871907a39aba5d918 100644
--- a/lib/compiler/implementation/ssa/builder.dart
+++ b/lib/compiler/implementation/ssa/builder.dart
@@ -2271,6 +2271,17 @@ class SsaBuilder implements Visitor {
     unreachable();
   }
 
+  visitCascade(Cascade node) {
+    visit(node.expression);
+    // Remove the result and reveal the duplicated receiver on the stack.
+    pop();
+  }
+
+  visitCascadeReceiver(CascadeReceiver node) {
+    visit(node.expression);
+    stack.add(stack.last());
+  }
+
   visitReturn(Return node) {
     HInstruction value;
     if (node.expression === null) {