Add a flag to track detached contexts.

src/bootstrapper.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/bootstrapper.h"
 
 #include "src/accessors.h"
 #include "src/code-stubs.h"
 #include "src/extensions/externalize-string-extension.h"
 #include "src/extensions/free-buffer-extension.h"
@@ skipping 355 matching lines @@
   JSObject::MigrateToMap(object, new_map);
 }
 
 
 void Bootstrapper::DetachGlobal(Handle<Context> env) {
   Factory* factory = env->GetIsolate()->factory();
   Handle<JSGlobalProxy> global_proxy(JSGlobalProxy::cast(env->global_proxy()));
   global_proxy->set_native_context(*factory->null_value());
   SetObjectPrototype(global_proxy, factory->null_value());
   global_proxy->map()->set_constructor(*factory->null_value());
+  if (FLAG_track_detached_contexts) {
+    env->GetIsolate()->AddDetachedContext(env);
+  }
 }
 
 
 static Handle<JSFunction> InstallFunction(Handle<JSObject> target,
                                           const char* name,
                                           InstanceType type,
                                           int instance_size,
                                           MaybeHandle<JSObject> maybe_prototype,
                                           Builtins::Name call) {
   Isolate* isolate = target->GetIsolate();
@@ skipping 2493 matching lines @@
   return from + sizeof(NestingCounterType);
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   DCHECK(!IsActive());
 }
 
 } }  // namespace v8::internal