Introduce LiteralsArray to hide it's implementation.

src/code-stubs-hydrogen.cc

Index: src/code-stubs-hydrogen.cc
diff --git a/src/code-stubs-hydrogen.cc b/src/code-stubs-hydrogen.cc
index 9f782225c1614648c95537e68bc08eb4ec7f0598..dc2ae554bfcf801dd653a8bf81de8cf65a03723a 100644
--- a/src/code-stubs-hydrogen.cc
+++ b/src/code-stubs-hydrogen.cc
@@ -442,8 +442,9 @@ HValue* CodeStubGraphBuilder<FastCloneShallowArrayStub>::BuildCodeStub() {
   // so that it doesn't build and eager frame.
   info()->MarkMustNotHaveEagerFrame();
 
-  HInstruction* allocation_site =
-      Add<HLoadKeyed>(GetParameter(0), GetParameter(1), nullptr, FAST_ELEMENTS);
+  HInstruction* allocation_site = Add<HLoadKeyed>(
+      GetParameter(0), GetParameter(1), nullptr, FAST_ELEMENTS,
+      NEVER_RETURN_HOLE, LiteralsArray::kOffsetToFirstLiteral - kHeapObjectTag);
   IfBuilder checker(this);
   checker.IfNot<HCompareObjectEqAndBranch, HValue*>(allocation_site,
                                                     undefined);
@@ -504,8 +505,9 @@ template <>
 HValue* CodeStubGraphBuilder<FastCloneShallowObjectStub>::BuildCodeStub() {
   HValue* undefined = graph()->GetConstantUndefined();
 
-  HInstruction* allocation_site =
-      Add<HLoadKeyed>(GetParameter(0), GetParameter(1), nullptr, FAST_ELEMENTS);
+  HInstruction* allocation_site = Add<HLoadKeyed>(
+      GetParameter(0), GetParameter(1), nullptr, FAST_ELEMENTS,
+      NEVER_RETURN_HOLE, LiteralsArray::kOffsetToFirstLiteral - kHeapObjectTag);
 
   IfBuilder checker(this);
   checker.IfNot<HCompareObjectEqAndBranch, HValue*>(allocation_site,