[turbofan] Properly handle dictionary maps in the prototype chain.

src/compilation-dependencies.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compilation-dependencies.h"
 
 #include "src/factory.h"
 #include "src/handles-inl.h"
 #include "src/isolate.h"
 #include "src/objects-inl.h"
@@ skipping 106 matching lines @@
 
 void CompilationDependencies::AssumeMapStable(Handle<Map> map) {
   DCHECK(map->is_stable());
   // Do nothing if the map cannot transition.
   if (map->CanTransition()) {
     Insert(DependentCode::kPrototypeCheckGroup, map);
   }
 }
 
 
-void CompilationDependencies::AssumePrototypeMapsStable(
-    Handle<Map> map, MaybeHandle<JSReceiver> prototype) {
-  for (PrototypeIterator i(map); !i.IsAtEnd(); i.Advance()) {
-    Handle<JSReceiver> const current =
-        PrototypeIterator::GetCurrent<JSReceiver>(i);
-    AssumeMapStable(handle(current->map()));
-    Handle<JSReceiver> last;
-    if (prototype.ToHandle(&last) && last.is_identical_to(current)) {
-      break;
-    }
-  }
-}
-
-
 void CompilationDependencies::AssumeTransitionStable(
     Handle<AllocationSite> site) {
   // Do nothing if the object doesn't have any useful element transitions left.
   ElementsKind kind =
       site->SitePointsToLiteral()
           ? JSObject::cast(site->transition_info())->GetElementsKind()
           : site->GetElementsKind();
   if (AllocationSite::GetMode(kind) == TRACK_ALLOCATION_SITE) {
     Insert(DependentCode::kAllocationSiteTransitionChangedGroup, site);
   }
 }
 
 }  // namespace internal
 }  // namespace v8