Mojo: Cancel WaitingCallbacks when their HandleWrappers are closed.

mojo/bindings/js/handle.cc

 // Copyright 2014 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 "mojo/bindings/js/handle.h"
 
 namespace gin {
 
 gin::WrapperInfo HandleWrapper::kWrapperInfo = { gin::kEmbedderNativeGin };
 
 HandleWrapper::HandleWrapper(MojoHandle handle)
     : handle_(mojo::Handle(handle)) {
 }
 
 HandleWrapper::~HandleWrapper() {
+  NotifyCloseObservers();
+}
+
+void HandleWrapper::Close() {
+  NotifyCloseObservers();
+  handle_.reset();
+}
+
+void HandleWrapper::AddCloseObserver(CloseObserver* observer) {
+  close_observers_.AddObserver(observer);
+}
+
+void HandleWrapper::RemoveCloseObserver(CloseObserver* observer) {
+  close_observers_.RemoveObserver(observer);
+}
+
+void HandleWrapper::NotifyCloseObservers() {
+  FOR_EACH_OBSERVER(CloseObserver, close_observers_, OnHandleClosed());

[sky, 2014/09/03 15:47:04]

Should we only notify the observers if the handle is valid when we get here? For
example, if someone explicitly invokes Close() and then deletes the
HandleWrapper do they really want two observer notifications?

[Sam McNally, 2014/09/08 04:31:52]

Done.

 }
 
 v8::Handle<v8::Value> Converter<mojo::Handle>::ToV8(v8::Isolate* isolate,
                                                     const mojo::Handle& val) {
   if (!val.is_valid())
     return v8::Null(isolate);
   return HandleWrapper::Create(isolate, val.value()).ToV8();
 }
 
 bool Converter<mojo::Handle>::FromV8(v8::Isolate* isolate,
                                      v8::Handle<v8::Value> val,
                                      mojo::Handle* out) {
   if (val->IsNull()) {
     *out = mojo::Handle();
     return true;
   }
 
   gin::Handle<HandleWrapper> handle;
   if (!Converter<gin::Handle<HandleWrapper> >::FromV8(isolate, val, &handle))
     return false;
 
   *out = handle->get();
   return true;
 }
 
 }  // namespace gin