Implement setSinkId() for media elements without src.

content/renderer/render_frame_impl.cc

 // Copyright 2013 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 "content/renderer/render_frame_impl.h"
 
 #include <map>
 #include <string>
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/debug/alias.h"
 #include "base/debug/asan_invalid_access.h"
 #include "base/debug/dump_without_crashing.h"
 #include "base/i18n/char_iterator.h"
 #include "base/metrics/histogram.h"
 #include "base/process/process.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "cc/base/switches.h"
 #include "components/scheduler/renderer/renderer_scheduler.h"
 #include "content/child/appcache/appcache_dispatcher.h"
 #include "content/child/permissions/permission_dispatcher.h"
 #include "content/child/plugin_messages.h"
 #include "content/child/quota_dispatcher.h"
 #include "content/child/request_extra_data.h"
 #include "content/child/service_worker/service_worker_handle_reference.h"
 #include "content/child/service_worker/service_worker_network_provider.h"
@@ skipping 41 matching lines @@
 #include "content/renderer/dom_automation_controller.h"
 #include "content/renderer/external_popup_menu.h"
 #include "content/renderer/geolocation_dispatcher.h"
 #include "content/renderer/gpu/gpu_benchmarking_extension.h"
 #include "content/renderer/history_controller.h"
 #include "content/renderer/history_serialization.h"
 #include "content/renderer/image_downloader/image_downloader_impl.h"
 #include "content/renderer/ime_event_guard.h"
 #include "content/renderer/internal_document_state_data.h"
 #include "content/renderer/manifest/manifest_manager.h"
+#include "content/renderer/media/audio_device_factory.h"
 #include "content/renderer/media/audio_renderer_mixer_manager.h"
 #include "content/renderer/media/crypto/render_cdm_factory.h"
 #include "content/renderer/media/media_permission_dispatcher_impl.h"
 #include "content/renderer/media/media_permission_dispatcher_proxy.h"
 #include "content/renderer/media/media_stream_dispatcher.h"
 #include "content/renderer/media/media_stream_renderer_factory_impl.h"
 #include "content/renderer/media/midi_dispatcher.h"
 #include "content/renderer/media/render_media_log.h"
 #include "content/renderer/media/user_media_client_impl.h"
 #include "content/renderer/media/webmediaplayer_ms.h"
@@ skipping 13 matching lines @@
 #include "content/renderer/renderer_webapplicationcachehost_impl.h"
 #include "content/renderer/renderer_webcolorchooser_impl.h"
 #include "content/renderer/savable_resources.h"
 #include "content/renderer/screen_orientation/screen_orientation_dispatcher.h"
 #include "content/renderer/shared_worker_repository.h"
 #include "content/renderer/skia_benchmarking_extension.h"
 #include "content/renderer/stats_collection_controller.h"
 #include "content/renderer/web_ui_extension.h"
 #include "content/renderer/websharedworker_proxy.h"
 #include "gin/modules/module_registry.h"
+#include "media/audio/audio_output_device.h"
 #include "media/base/audio_renderer_mixer_input.h"
 #include "media/base/media_log.h"
 #include "media/blink/webencryptedmediaclient_impl.h"
 #include "media/blink/webmediaplayer_impl.h"
 #include "media/renderers/gpu_video_accelerator_factories.h"
 #include "mojo/common/url_type_converters.h"
 #include "net/base/data_url.h"
 #include "net/base/net_errors.h"
 #include "net/base/registry_controlled_domains/registry_controlled_domain.h"
 #include "net/http/http_util.h"
@@ skipping 5162 matching lines @@
   DCHECK(mojo_shell_);
   mojo::ServiceProviderPtr service_provider;
   mojo::URLRequestPtr request(mojo::URLRequest::New());
   request->url = mojo::String::From(url);
   mojo_shell_->ConnectToApplication(request.Pass(), GetProxy(&service_provider),
                                     nullptr, nullptr,
                                     base::Bind(&OnGotContentHandlerID));
   return service_provider.Pass();
 }
 
+void RenderFrameImpl::checkIfAudioSinkExistsAndIsAuthorized(
+    const blink::WebString& sink_id,
+    const blink::WebSecurityOrigin& security_origin,
+    blink::WebSetSinkIdCallbacks* web_callback) {
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
+      FROM_HERE,
+      base::Bind(&RenderFrameImpl::DoCheckIfAudioSinkExistsAndIsAuthorized,

[Peter Beverloo, 2015/11/09 20:05:06]

There is a really subtle case in which this PostTask matters (even though the
implementation of the check is synchronous) - while resolving the promise will
use a microtask and thus appear asynchronous to the developer, not having this
PostTask would cause HTMLMediaElementAudioOutputDevice.m_sinkId to be
synchronously updated, which *can* be observed.

Firstly, I think it would be worth documenting this somewhere - perhaps add a
comment here briefly explaining why the PostTask to the same thread matters, it
may confuse a reader.

Secondly, this would be a good case to test in the layout test, which now
doesn't check the `sinkId` property at all.

  (1) Assert that element.sinkId == ''
  (2) Call element.setSinkId('somevalue')
  (3) Assert that element.sinkId == ''
  (4) Once the promise resolves, element.sinkId == 'somevalue'

(Are there keywords we can use for this kind of pass-through?)

[Guido Urdaneta, 2015/11/10 15:36:51]

I changed the implementation so that it is made asynchronous in Blink.
The reason is that when I added the mock version of
checkIfAudioSinkExistsAndIsAuthorized() to WebFrameTestProxy, the promise was
resolved/rejected too quickly and the layout test was getting undefined as the
result of setSinkId() instead of a Promise object. I don't know if this is a
feature or a bug, but it did not happen in tests when the real implementation
was used.
The sinkId property check was added to the test.

+                 weak_factory_.GetWeakPtr(), sink_id.utf8(),
+                 static_cast<url::Origin>(security_origin),
+                 media::ConvertToSwitchOutputDeviceCB(web_callback)));
+}
+
+void RenderFrameImpl::DoCheckIfAudioSinkExistsAndIsAuthorized(
+    const std::string& device_id,
+    const url::Origin& security_origin,
+    const media::SwitchOutputDeviceCB& callback) {
+  scoped_refptr<media::AudioOutputDevice> device =
+      AudioDeviceFactory::NewOutputDevice(routing_id_, 0, device_id,
+                                          security_origin);
+  media::OutputDeviceStatus status = device->GetDeviceStatus();
+  device->Stop();
+  callback.Run(status);
+}
+
 }  // namespace content