Use Unique<Map> in HTransitionElementsKind.

src/arm/lithium-arm.h

Index: src/arm/lithium-arm.h
diff --git a/src/arm/lithium-arm.h b/src/arm/lithium-arm.h
index 9c91a030044346e1b75763caff118d125523cdfa..3902b4c97b00bc056b11ab0d856c3e6694dca2fa 100644
--- a/src/arm/lithium-arm.h
+++ b/src/arm/lithium-arm.h
@@ -2276,8 +2276,10 @@ class LTransitionElementsKind V8_FINAL : public LTemplateInstruction<0, 1, 1> {
 
   virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
 
-  Handle<Map> original_map() { return hydrogen()->original_map(); }
-  Handle<Map> transitioned_map() { return hydrogen()->transitioned_map(); }
+  Handle<Map> original_map() { return hydrogen()->original_map().handle(); }
+  Handle<Map> transitioned_map() {
+    return hydrogen()->transitioned_map().handle();
+  }
   ElementsKind from_kind() { return hydrogen()->from_kind(); }
   ElementsKind to_kind() { return hydrogen()->to_kind(); }
 };