Make sure gin Handles exist before using them

content/renderer/dom_automation_controller.cc

 // Copyright (c) 2012 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 "content/renderer/dom_automation_controller.h"
 
 #include "base/json/json_string_value_serializer.h"
 #include "base/strings/string_util.h"
 #include "content/common/child_process_messages.h"
 #include "content/common/frame_messages.h"
@@ skipping 15 matching lines @@
   v8::Isolate* isolate = blink::mainThreadIsolate();
   v8::HandleScope handle_scope(isolate);
   v8::Handle<v8::Context> context = frame->mainWorldScriptContext();
   if (context.IsEmpty())
     return;
 
   v8::Context::Scope context_scope(context);
 
   gin::Handle<DomAutomationController> controller =
       gin::CreateHandle(isolate, new DomAutomationController(render_frame));
+  if (controller.IsEmpty())
+    return;
+
   v8::Handle<v8::Object> global = context->Global();
   global->Set(gin::StringToV8(isolate, "domAutomationController"),
               controller.ToV8());
 }
 
 DomAutomationController::DomAutomationController(RenderFrame* render_frame)
     : RenderFrameObserver(render_frame), automation_id_(MSG_ROUTING_NONE) {}
 
 DomAutomationController::~DomAutomationController() {}
 
@@ skipping 65 matching lines @@
   return Send(
       new FrameHostMsg_DomOperationResponse(routing_id(), str, automation_id));
 }
 
 bool DomAutomationController::SetAutomationId(int automation_id) {
   automation_id_ = automation_id;
   return true;
 }
 
 }  // namespace content