Split TemplateHashMapImpl::Lookup into two methods

src/ast-value-factory.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 345 matching lines @@
 
 #undef GENERATE_VALUE_GETTER
 
 AstRawString* AstValueFactory::GetString(uint32_t hash, bool is_one_byte,
                                          Vector<const byte> literal_bytes) {
   // literal_bytes here points to whatever the user passed, and this is OK
   // because we use vector_compare (which checks the contents) to compare
   // against the AstRawStrings which are in the string_table_. We should not
   // return this AstRawString.
   AstRawString key(is_one_byte, literal_bytes, hash);
-  HashMap::Entry* entry = string_table_.Lookup(&key, hash, true);
+  HashMap::Entry* entry = string_table_.LookupOrInsert(&key, hash);
   if (entry->value == NULL) {
     // Copy literal contents for later comparison.
     int length = literal_bytes.length();
     byte* new_literal_bytes = zone_->NewArray<byte>(length);
     memcpy(new_literal_bytes, literal_bytes.start(), length);
     AstRawString* new_string = new (zone_) AstRawString(
         is_one_byte, Vector<const byte>(new_literal_bytes, length), hash);
     entry->key = new_string;
     strings_.Add(new_string);
     if (isolate_) {
       new_string->Internalize(isolate_);
     }
     entry->value = reinterpret_cast<void*>(1);
   }
   return reinterpret_cast<AstRawString*>(entry->key);
 }
 
 
 } }  // namespace v8::internal