Add initialization for has_external_callback field.

src/log.cc

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 132 matching lines @@
 
 
 //
 // StackTracer implementation
 //
 void StackTracer::Trace(Isolate* isolate, TickSample* sample) {
   ASSERT(isolate->IsInitialized());
 
   sample->tos = NULL;
   sample->frames_count = 0;
+  sample->has_external_callback = false;
 
   // Avoid collecting traces while doing GC.
   if (sample->state == GC) return;
 
   const Address js_entry_sp =
       Isolate::js_entry_sp(isolate->thread_local_top());
   if (js_entry_sp == 0) {
     // Not executing JS now.
     return;
   }
@@ skipping 1493 matching lines @@
 void SamplerRegistry::RemoveActiveSampler(Sampler* sampler) {
   ASSERT(sampler->IsActive());
   ScopedLock lock(mutex_);
   ASSERT(active_samplers_ != NULL);
   bool removed = active_samplers_->RemoveElement(sampler);
   ASSERT(removed);
   USE(removed);
 }
 
 } }  // namespace v8::internal