Make HCapturedObjects non-deletable for DCE.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 66050f1398c1da307365f11854be912f3a39afc3..744ab794310cf06e7828ae333bf43265dbaf3708 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -3258,9 +3258,6 @@ class HDematerializedObject : public HInstruction {
 
   // List of values tracked by this marker.
   ZoneList<HValue*> values_;
-
- private:
-  virtual bool IsDeletable() const V8_FINAL V8_OVERRIDE { return true; }
 };
 
 
@@ -3288,6 +3285,8 @@ class HArgumentsObject V8_FINAL : public HDematerializedObject {
     set_representation(Representation::Tagged());
     SetFlag(kIsArguments);
   }
+
+  virtual bool IsDeletable() const V8_FINAL V8_OVERRIDE { return true; }
 };
 
 
@@ -3324,6 +3323,11 @@ class HCapturedObject V8_FINAL : public HDematerializedObject {
 
  private:
   int capture_id_;
+
+  // Note that we cannot DCE captured objects as they are used to replay
+  // the environment. This method is here as an explicit reminder.
+  // TODO(mstarzinger): Turn HSimulates into full snapshots maybe?
+  virtual bool IsDeletable() const V8_FINAL V8_OVERRIDE { return false; }
 };