When an Isolate is configured to use lockers, foreground tasks need to lock

gin/isolate_holder.cc

Index: gin/isolate_holder.cc
diff --git a/gin/isolate_holder.cc b/gin/isolate_holder.cc
index 5252400c13c5572251f72dcfb5b5e86c95ec3685..04449d26ab5657712c8c35d64da65b20424852ea 100644
--- a/gin/isolate_holder.cc
+++ b/gin/isolate_holder.cc
@@ -41,7 +41,7 @@ IsolateHolder::IsolateHolder(AccessMode access_mode)
                                        base::SysInfo::AmountOfVirtualMemory());
   params.array_buffer_allocator = allocator;
   isolate_ = v8::Isolate::New(params);
-  isolate_data_.reset(new PerIsolateData(isolate_, allocator));
+  isolate_data_.reset(new PerIsolateData(isolate_, allocator, access_mode));
   isolate_memory_dump_provider_.reset(new V8IsolateMemoryDumpProvider(this));
 #if defined(OS_WIN)
   {