[Extensions Bindings] Notify of event unregistration on invalidation

extensions/renderer/api_bindings_system.cc

 // Copyright 2016 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 "extensions/renderer/api_bindings_system.h"
 
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "base/values.h"
 #include "extensions/renderer/api_binding_hooks.h"
@@ skipping 106 matching lines @@
   return hooks.get();
 }
 
 void APIBindingsSystem::RegisterCustomType(const std::string& type_name,
                                            const CustomTypeHandler& function) {
   DCHECK(custom_types_.find(type_name) == custom_types_.end())
       << "Custom type already registered: " << type_name;
   custom_types_[type_name] = function;
 }
 
+void APIBindingsSystem::WillReleaseContext(v8::Local<v8::Context> context) {
+  event_handler_.InvalidateContext(context);
+}
+
 v8::Local<v8::Object> APIBindingsSystem::CreateCustomType(
     v8::Local<v8::Context> context,
     const std::string& type_name,
     const std::string& property_name) {
   auto iter = custom_types_.find(type_name);
   DCHECK(iter != custom_types_.end()) << "Custom type not found: " << type_name;
   return iter->second.Run(context, property_name, &request_handler_,
                           &type_reference_map_);
 }
 
 }  // namespace extensions