Added a check for the utf8 string input being empty (NULL).

chrome/renderer/external_extension.cc

 // Copyright (c) 2009 The Chromium 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 "chrome/renderer/external_extension.h"
 
 #include "base/command_line.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/search_provider.h"
@@ skipping 125 matching lines @@
     }
   }
 
   return v8::Undefined();
 }
 
 // static
 v8::Handle<v8::Value> ExternalExtensionWrapper::IsSearchProviderInstalled(
     const v8::Arguments& args) {
   if (!args.Length()) return v8::Undefined();
+  v8::String::Utf8Value utf8name(args[0]);
+  if (!utf8name.length()) return v8::Undefined();
 
-  std::string name = std::string(*v8::String::Utf8Value(args[0]));
-  if (!name.length()) return v8::Undefined();
-
+  std::string name = std::string(*utf8name);
   RenderView* render_view = GetRenderView();
   if (!render_view) return v8::Undefined();
 
   WebFrame* webframe = WebFrame::frameForEnteredContext();
   if (!webframe) return v8::Undefined();
 
   search_provider::InstallState install = search_provider::DENIED;
   GURL inquiry_url = GURL(name);
   if (!inquiry_url.is_empty()) {
       render_view->Send(new ViewHostMsg_GetSearchProviderInstallState(
           render_view->routing_id(), webframe->url(), inquiry_url, &install));
   }
 
   if (install == search_provider::DENIED) {
     // FIXME: throw access denied exception.
     return v8::ThrowException(v8::Exception::Error(v8::String::Empty()));
   }
   return v8::Integer::New(install);
 }
 
 v8::Extension* ExternalExtension::Get() {
   return new ExternalExtensionWrapper();
 }
 
 }  // namespace extensions_v8