First simple implementation of for-of in TurboFan.

src/compiler/control-builders.h

Index: src/compiler/control-builders.h
diff --git a/src/compiler/control-builders.h b/src/compiler/control-builders.h
index e8e3305db2800608e4925c386a87279924fca8b0..ba04107dbc54f838dfcdbe7ccbff3691577992a5 100644
--- a/src/compiler/control-builders.h
+++ b/src/compiler/control-builders.h
@@ -77,8 +77,9 @@ class LoopBuilder FINAL : public ControlBuilder {
   void Continue() FINAL;
   void Break() FINAL;
 
-  // Compound control command for conditional break.
+  // Compound control commands for conditional break.
   void BreakUnless(Node* condition);
+  void BreakWhen(Node* condition);
 
  private:
   Environment* loop_environment_;      // Environment of the loop header.