Fix weak processing over cleared hash tables.

third_party/WebKit/Source/wtf/HashTable.h

Index: third_party/WebKit/Source/wtf/HashTable.h
diff --git a/third_party/WebKit/Source/wtf/HashTable.h b/third_party/WebKit/Source/wtf/HashTable.h
index 14ceab4051513ccc53608aab4fdc932873ae6c5c..86222a37f4cab02ce645cced7ac486a349e47515 100644
--- a/third_party/WebKit/Source/wtf/HashTable.h
+++ b/third_party/WebKit/Source/wtf/HashTable.h
@@ -1276,7 +1276,8 @@ struct WeakProcessingHashTableHelper<WeakHandlingInCollections, Key, Value, Extr
     {
         typedef HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits, Allocator> HashTableType;
         HashTableType* table = reinterpret_cast<HashTableType*>(closure);
-        ASSERT(table->m_table);
+        if (!table->m_table)
+            return;
         // Now perform weak processing (this is a no-op if the backing was
         // accessible through an iterator and was already marked strongly).
         typedef typename HashTableType::ValueType ValueType;