Revert of Serializer: clear string hash for code serializer.

src/snapshot/serialize.cc

Index: src/snapshot/serialize.cc
diff --git a/src/snapshot/serialize.cc b/src/snapshot/serialize.cc
index 8b382c09fb1a3c047a1c22f02dd2dc3ad9703b42..57092e1b46238336fff16a11e9a510324fbceea4 100644
--- a/src/snapshot/serialize.cc
+++ b/src/snapshot/serialize.cc
@@ -714,16 +714,20 @@
 
 HeapObject* Deserializer::PostProcessNewObject(HeapObject* obj, int space) {
   if (deserializing_user_code()) {
-    if (obj->IsInternalizedString()) {
-      // Canonicalize the internalized string. If it already exists in the
-      // string table, set it to forward to the existing one.
-      DisallowHeapAllocation no_gc;
+    if (obj->IsString()) {
       String* string = String::cast(obj);
-      HandleScope scope(isolate_);
-      StringTableInsertionKey key(string);
-      String* canonical = *StringTable::LookupKey(isolate_, &key);
-      string->SetForwardedInternalizedString(canonical);
-      return canonical;
+      // Uninitialize hash field as the hash seed may have changed.
+      string->set_hash_field(String::kEmptyHashField);
+      if (string->IsInternalizedString()) {
+        // Canonicalize the internalized string. If it already exists in the
+        // string table, set it to forward to the existing one.
+        DisallowHeapAllocation no_gc;
+        HandleScope scope(isolate_);
+        StringTableInsertionKey key(string);
+        String* canonical = *StringTable::LookupKey(isolate_, &key);
+        string->SetForwardedInternalizedString(canonical);
+        return canonical;
+      }
     } else if (obj->IsScript()) {
       // Assign a new script id to avoid collision.
       Script::cast(obj)->set_id(isolate_->heap()->NextScriptId());
@@ -2300,24 +2304,12 @@
 void CodeSerializer::SerializeGeneric(HeapObject* heap_object,
                                       HowToCode how_to_code,
                                       WhereToPoint where_to_point) {
-  int string_hash = String::kEmptyHashField;
-  if (heap_object->IsString()) {
-    String* string = String::cast(heap_object);
-    if (string->IsInternalizedString()) num_internalized_strings_++;
-    // Temporarily clear string hash.
-    string_hash = string->hash_field();
-    string->set_hash_field(String::kEmptyHashField);
-  }
+  if (heap_object->IsInternalizedString()) num_internalized_strings_++;
 
   // Object has not yet been serialized.  Serialize it here.
   ObjectSerializer serializer(this, heap_object, sink_, how_to_code,
                               where_to_point);
   serializer.Serialize();
-
-  if (string_hash != String::kEmptyHashField) {
-    // Restore string hash.
-    String::cast(heap_object)->set_hash_field(String::kEmptyHashField);
-  }
 }