Small MessageLocation related refactoring.

src/runtime/runtime-internal.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 "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/bootstrapper.h"
 #include "src/conversions.h"
 #include "src/debug/debug.h"
@@ skipping 238 matching lines @@
         isolate, isolate->CaptureAndSetSimpleStackTrace(error_object, caller));
   }
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(Runtime_RenderCallSite) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 0);
   MessageLocation location;
-  isolate->ComputeLocation(&location);
-  if (location.start_pos() == -1) return isolate->heap()->empty_string();
+  if (!isolate->ComputeLocation(&location)) {
+    return isolate->heap()->empty_string();
+  }
 
   Zone zone;
   base::SmartPointer<ParseInfo> info(
       location.function()->shared()->is_function()
           ? new ParseInfo(&zone, location.function())
           : new ParseInfo(&zone, location.script()));
 
   if (!Parser::ParseStatic(info.get())) {
     isolate->clear_pending_exception();
     return isolate->heap()->empty_string();
@@ skipping 142 matching lines @@
 }
 
 
 RUNTIME_FUNCTION(Runtime_GetCodeStubExportsObject) {
   HandleScope shs(isolate);
   return isolate->heap()->code_stub_exports_object();
 }
 
 }  // namespace internal
 }  // namespace v8