Make the crashed web platform pointerevent tests pass

content/renderer/gpu/gpu_benchmarking_extension.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/gpu/gpu_benchmarking_extension.h"
 
 #include <stddef.h>
 
 #include <string>
 #include <utility>
@@ skipping 291 matching lines @@
         1,
         argv);
   }
 }
 
 void OnSyntheticGestureCompleted(CallbackAndContext* callback_and_context) {
   v8::Isolate* isolate = callback_and_context->isolate();
   v8::HandleScope scope(isolate);
   v8::Local<v8::Context> context = callback_and_context->GetContext();
   v8::Context::Scope context_scope(context);
+  v8::Local<v8::Function> callback = callback_and_context->GetCallback();
   WebLocalFrame* frame = WebLocalFrame::frameForContext(context);
-  if (frame) {
+  if (frame && !callback.IsEmpty()) {
     frame->callFunctionEvenIfScriptDisabled(
-        callback_and_context->GetCallback(), v8::Object::New(isolate), 0, NULL);
+        callback, v8::Object::New(isolate), 0, NULL);
   }
 }
 
 bool BeginSmoothScroll(v8::Isolate* isolate,
                        float pixels_to_scroll,
                        v8::Local<v8::Function> callback,
                        int gesture_source_type,
                        const std::string& direction,
                        float speed_in_pixels_s,
                        bool prevent_fling,
@@ skipping 633 matching lines @@
           &gpu_driver_bug_workarounds))) {
     return;
   }
 
   v8::Local<v8::Value> result;
   if (gin::TryConvertToV8(args->isolate(), gpu_driver_bug_workarounds, &result))
     args->Return(result);
 }
 
 }  // namespace content