Return MaybeHandle from Invoke.

src/isolate.cc

 // Copyright 2012 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 1113 matching lines @@
               stack_trace_for_uncaught_exceptions_frame_limit_,
               stack_trace_for_uncaught_exceptions_options_);
         }
       }
 
       Handle<Object> exception_arg = exception_handle;
       // If the exception argument is a custom object, turn it into a string
       // before throwing as uncaught exception.  Note that the pending
       // exception object to be set later must not be turned into a string.
       if (exception_arg->IsJSObject() && !IsErrorObject(exception_arg)) {
-        bool failed = false;
-        exception_arg =
-            Execution::ToDetailString(this, exception_arg, &failed);
-        if (failed) {
+        MaybeHandle<Object> maybe_exception =
+            Execution::ToDetailString(this, exception_arg);
+        if (!maybe_exception.ToHandle(&exception_arg)) {
           exception_arg = factory()->InternalizeOneByteString(
               STATIC_ASCII_VECTOR("exception"));
         }
       }
       Handle<Object> message_obj = MessageHandler::MakeMessageObject(
           this,
           "uncaught_exception",
           location,
           HandleVector<Object>(&exception_arg, 1),
           stack_trace_object);
@@ skipping 1140 matching lines @@
       Handle<JSObject> obj = factory()->NewJSObjectFromMap(map);
       JSObject::NormalizeProperties(obj, KEEP_INOBJECT_PROPERTIES, 8);
       JSObject::SetProperty(registry, name, obj, NONE, STRICT).Assert();
     }
   }
   return Handle<JSObject>::cast(factory()->symbol_registry());
 }
 
 
 } }  // namespace v8::internal