Provide a counter for thrown JavaScript errors per context

src/factory.cc

 // Copyright 2014 the V8 project 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 "src/factory.h"
 
 #include "src/allocation-site-scopes.h"
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
 #include "src/conversions.h"
@@ skipping 709 matching lines @@
   return symbol;
 }
 
 
 Handle<Context> Factory::NewNativeContext() {
   Handle<FixedArray> array =
       NewFixedArray(Context::NATIVE_CONTEXT_SLOTS, TENURED);
   array->set_map_no_write_barrier(*native_context_map());
   Handle<Context> context = Handle<Context>::cast(array);
   context->set_js_array_maps(*undefined_value());
+  context->set_errors_thrown(Smi::FromInt(0));
   DCHECK(context->IsNativeContext());
   return context;
 }
 
 
 Handle<Context> Factory::NewScriptContext(Handle<JSFunction> function,
                                           Handle<ScopeInfo> scope_info) {
   Handle<FixedArray> array =
       NewFixedArray(scope_info->ContextLength(), TENURED);
   array->set_map_no_write_barrier(*script_context_map());
@@ skipping 1662 matching lines @@
 }
 
 
 Handle<Object> Factory::ToBoolean(bool value) {
   return value ? true_value() : false_value();
 }
 
 
 }  // namespace internal
 }  // namespace v8