[Media Router] Use DialMediaSinkService in MediaRouterMojoImpl

chrome/browser/media/router/discovery/dial/dial_media_sink_service_delegate.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/dial/dial_media_sink_service_delegate.h"
+
+#include "chrome/browser/media/router/discovery/dial/dial_media_sink_service.h"
+
+using content::BrowserThread;
+
+namespace media_router {
+
+DialMediaSinkServiceDelegate::DialMediaSinkServiceDelegate() {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+}
+
+DialMediaSinkServiceDelegate::~DialMediaSinkServiceDelegate() {}
+
+void DialMediaSinkServiceDelegate::Start(
+    const MediaSinkService::OnSinksDiscoveredCallback& callback,
+    net::URLRequestContextGetter* request_context) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  sink_discovery_ui_callback_ = callback;
+
+  content::BrowserThread::PostTask(
+      content::BrowserThread::IO, FROM_HERE,
+      base::Bind(&DialMediaSinkServiceDelegate::StartOnIOThread, this,
+                 request_context));
+}
+
+void DialMediaSinkServiceDelegate::Stop() {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  sink_discovery_ui_callback_.Reset();
+
+  content::BrowserThread::PostTask(
+      content::BrowserThread::IO, FROM_HERE,
+      base::Bind(&DialMediaSinkServiceDelegate::StopOnIOThread, this));
+}
+
+void DialMediaSinkServiceDelegate::SetDialMediaSinkServiceForTest(
+    std::unique_ptr<DialMediaSinkService,
+                    content::BrowserThread::DeleteOnIOThread>
+        dial_media_sink_service) {
+  dial_media_sink_service_ = std::move(dial_media_sink_service);

[mark a. foltz, 2017/05/12 21:37:37]

Ensure this is set only once? E.g., before this line

DCHECK(dial_media_sink_service)
DCHECK(!dial_media_sink_service_)

[zhaobin, 2017/05/12 23:03:38]

Done.

+}
+
+void DialMediaSinkServiceDelegate::StartOnIOThread(
+    net::URLRequestContextGetter* request_context) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);

[mark a. foltz, 2017/05/12 21:37:36]

Nit: as this is a private method, may not be necessary to check threading here.

[zhaobin, 2017/05/12 23:03:38]

Done.

+  if (!dial_media_sink_service_) {

[mark a. foltz, 2017/05/12 21:37:36]

Is Start()/Stop()/Start() okay?

[zhaobin, 2017/05/12 23:03:38]

Yes. MediaRouterMojoImpl will only do Start()/Stop() though.

+    dial_media_sink_service_.reset(new DialMediaSinkService(
+        base::Bind(&DialMediaSinkServiceDelegate::OnSinksDiscoveredOnIOThread,
+                   base::Unretained(this)),
+        request_context));
+  }
+  dial_media_sink_service_->Start();

[mark a. foltz, 2017/05/12 21:37:37]

Do you need to check that the service is not already started?

[zhaobin, 2017/05/12 23:03:38]

Handled in unserlying DialMediaSinkService.

+}
+
+void DialMediaSinkServiceDelegate::StopOnIOThread() {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  DCHECK(dial_media_sink_service_);
+  dial_media_sink_service_->Stop();

[mark a. foltz, 2017/05/12 21:37:37]

Do you need to check that the service is not already stopped?

[zhaobin, 2017/05/12 23:03:38]

Handled in unserlying DialMediaSinkService.

+}
+
+void DialMediaSinkServiceDelegate::OnSinksDiscoveredOnIOThread(
+    const std::vector<MediaSinkInternal>& sinks) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&DialMediaSinkServiceDelegate::OnSinksDiscoveredOnUIThread,
+                 this,
+                 std::vector<MediaSinkInternal>(sinks.begin(), sinks.end())));
+}
+
+void DialMediaSinkServiceDelegate::OnSinksDiscoveredOnUIThread(
+    const std::vector<MediaSinkInternal>& sinks) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);

[mark a. foltz, 2017/05/12 21:37:37]

This is only called from a private callback - thread check not necessary.

[zhaobin, 2017/05/12 23:03:38]

Done.

+  if (sink_discovery_ui_callback_)
+    sink_discovery_ui_callback_.Run(sinks);
+}
+
+}  // namespace media_router