[explicit isolates] Eliminate most GetIsolates in snapshot/

Use a passed in Isolate/Heap directly rather than using GetIsolate() on
HeapObjects which may not in future be tied to an isolate.

Bug: v8:7786
Change-Id: I89d8706544aa135049434cf20c4e1308474c678b
Reviewed-on: https://chromium-review.googlesource.com/1089334Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53569}

src/snapshot/code-serializer.cc

@@ -268,7 +268,7 @@ MaybeHandle<SharedFunctionInfo> CodeSerializer::Deserialize(
   if (sanity_check_result != SerializedCodeData::CHECK_SUCCESS) {
     if (FLAG_profile_deserialization) PrintF("[Cached code failed check]\n");
     DCHECK(cached_data->rejected());
-    source->GetIsolate()->counters()->code_cache_reject_reason()->AddSample(
+    isolate->counters()->code_cache_reject_reason()->AddSample(
         sanity_check_result);
     return MaybeHandle<SharedFunctionInfo>();
   }

src/snapshot/deserializer.cc

@@ -161,11 +161,11 @@ HeapObject* Deserializer<AllocatorT>::PostProcessNewObject(HeapObject* obj,
 
         if (canonical != nullptr) return canonical;
 
-        new_internalized_strings_.push_back(handle(string));
+        new_internalized_strings_.push_back(handle(string, isolate_));
         return string;
       }
     } else if (obj->IsScript()) {
-      new_scripts_.push_back(handle(Script::cast(obj)));
+      new_scripts_.push_back(handle(Script::cast(obj), isolate_));
     } else {
       DCHECK(CanBeDeferred(obj));
     }

src/snapshot/object-deserializer.cc

@@ -79,7 +79,7 @@ MaybeHandle<HeapObject> ObjectDeserializer::Deserialize(Isolate* isolate) {
     VisitRootPointer(Root::kPartialSnapshotCache, nullptr, &root);
     DeserializeDeferredObjects();
     FlushICacheForNewCodeObjectsAndRecordEmbeddedObjects();
-    result = Handle<HeapObject>(HeapObject::cast(root));
+    result = handle(HeapObject::cast(root), isolate);
     Rehash();
     allocator()->RegisterDeserializedObjectsForBlackAllocation();
   }

src/snapshot/serializer.cc

@@ -576,12 +576,12 @@ void Serializer<
 // TODO(all): replace this with proper iteration of weak slots in serializer.
 class UnlinkWeakNextScope {
  public:
-  explicit UnlinkWeakNextScope(HeapObject* object) : object_(nullptr) {
+  explicit UnlinkWeakNextScope(Heap* heap, HeapObject* object)
+      : object_(nullptr) {
     if (object->IsAllocationSite()) {
       object_ = object;
       next_ = AllocationSite::cast(object)->weak_next();
-      AllocationSite::cast(object)->set_weak_next(
-          object->GetHeap()->undefined_value());
+      AllocationSite::cast(object)->set_weak_next(heap->undefined_value());
     }
   }
 
@@ -695,7 +695,7 @@ void Serializer<AllocatorT>::ObjectSerializer::SerializeDeferred() {
 template <class AllocatorT>
 void Serializer<AllocatorT>::ObjectSerializer::SerializeContent(Map* map,
                                                                 int size) {
-  UnlinkWeakNextScope unlink_weak_next(object_);
+  UnlinkWeakNextScope unlink_weak_next(serializer_->isolate()->heap(), object_);
   if (object_->IsCode()) {
     // For code objects, output raw bytes first.
     OutputCode(size);