[Media Router] Create MediaSinkServiceBase and make DialMediaSinkService inherit from it

chrome/browser/media/router/discovery/media_sink_service_base.cc

+// Copyright 2017 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 "chrome/browser/media/router/discovery/media_sink_service_base.h"
+
+#include <vector>
+
+namespace {
+// Time interval when media sink service sends sinks to MRP.
+const int kFetchCompleteTimeoutSecs = 3;
+}
+
+namespace media_router {
+
+MediaSinkServiceBase::MediaSinkServiceBase(
+    const OnSinksDiscoveredCallback& callback)
+    : MediaSinkService(callback) {
+  fetch_complete_timeout_secs_ = kFetchCompleteTimeoutSecs;
+}
+
+MediaSinkServiceBase::~MediaSinkServiceBase() = default;
+
+void MediaSinkServiceBase::SetTimerForTest(std::unique_ptr<base::Timer> timer) {
+  DCHECK(!finish_timer_);
+  finish_timer_ = std::move(timer);
+}
+
+void MediaSinkServiceBase::OnFetchCompleted() {
+  DCHECK(!sink_discovery_callback_.is_null());
+
+  if (current_sinks_ == mrp_sinks_) {
+    DVLOG(2) << "No update to sink list.";
+    return;
+  }
+
+  DVLOG(2) << "Send sinks to media router, [size]: " << current_sinks_.size();
+  sink_discovery_callback_.Run(std::vector<MediaSinkInternal>(
+      current_sinks_.begin(), current_sinks_.end()));
+  mrp_sinks_ = current_sinks_;
+}
+
+void MediaSinkServiceBase::StartTimer() {
+  // Create a finish timer.
+  if (!finish_timer_)
+    finish_timer_.reset(new base::OneShotTimer());
+
+  base::TimeDelta finish_delay =
+      base::TimeDelta::FromSeconds(fetch_complete_timeout_secs_);
+  finish_timer_->Start(FROM_HERE, finish_delay,
+                       base::Bind(&MediaSinkServiceBase::OnFetchCompleted,
+                                  base::Unretained(this)));
+}
+
+}  // namespace media_router