Return MaybeHandle from NewExternalStringFrom*.

src/factory.cc

 // Copyright 2014 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 "factory.h"
 
 #include "isolate-inl.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 500 matching lines @@
                                      : String::TWO_BYTE_ENCODING);
 
   slice->set_hash_field(String::kEmptyHashField);
   slice->set_length(length);
   slice->set_parent(*str);
   slice->set_offset(offset);
   return slice;
 }
 
 
-Handle<String> Factory::NewExternalStringFromAscii(
+MaybeHandle<String> Factory::NewExternalStringFromAscii(
     const ExternalAsciiString::Resource* resource) {
   CALL_HEAP_FUNCTION(
       isolate(),
       isolate()->heap()->AllocateExternalStringFromAscii(resource),
       String);
 }
 
 
-Handle<String> Factory::NewExternalStringFromTwoByte(
+MaybeHandle<String> Factory::NewExternalStringFromTwoByte(
     const ExternalTwoByteString::Resource* resource) {
   CALL_HEAP_FUNCTION(
       isolate(),
       isolate()->heap()->AllocateExternalStringFromTwoByte(resource),
       String);
 }
 
 
 Handle<Symbol> Factory::NewSymbol() {
   CALL_HEAP_FUNCTION(
@@ skipping 1405 matching lines @@
   if (name->Equals(h->infinity_string())) return infinity_value();
   return Handle<Object>::null();
 }
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return value ? true_value() : false_value();
 }
 
 } }  // namespace v8::internal