NOT INTENDED FOR LANDING: A promises demo

components/scheduler/promises/single_thread_promise_executor.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 "components/scheduler/promises/single_thread_promise_executor.h"
+
+#include "base/bind.h"
+
+namespace promise {
+namespace internal {
+
+SingleThreadPromiseExecutor::SingleThreadPromiseExecutor(
+    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner)
+    : task_runner_(task_runner) {}
+
+SingleThreadPromiseExecutor::~SingleThreadPromiseExecutor() {}
+
+void SingleThreadPromiseExecutor::StartResolveInternal(PromiseBase* promise) {
+  PromiseExecutor::StartResolveInternal(promise);
+  DispatchResolveImpl();
+}
+
+void SingleThreadPromiseExecutor::ResolveImpl() {
+  PromiseBase* ready_promise = GetNextReadyPromise();
+  if (!ready_promise)
+    return;
+  ResolvePromise(ready_promise);
+}
+
+void SingleThreadPromiseExecutor::DispatchResolveImpl() {
+  task_runner_->PostTask(FROM_HERE,
+                         base::Bind(&SingleThreadPromiseExecutor::ResolveImpl,
+                                    base::Unretained(this)));
+}
+
+bool SingleThreadPromiseExecutor::OnPromiseResolved(PromiseBase* promise) {
+  if (PromiseExecutor::OnPromiseResolved(promise))
+    DispatchResolveImpl();
+  return false;
+}
+
+bool SingleThreadPromiseExecutor::OnPromiseRejected(PromiseBase* promise) {
+  if (PromiseExecutor::OnPromiseRejected(promise))
+    DispatchResolveImpl();
+  return false;
+}
+
+}  // namespace internal
+}  // namespace promise