Add mojo interface+impl creation of audio streams.

content/browser/renderer_host/media/render_frame_audio_output_stream_factory.cc

Index: content/browser/renderer_host/media/render_frame_audio_output_stream_factory.cc
diff --git a/content/browser/renderer_host/media/render_frame_audio_output_stream_factory.cc b/content/browser/renderer_host/media/render_frame_audio_output_stream_factory.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3e078343a3de21f4e3c8a95fb5d2f6f324039cc3
--- /dev/null
+++ b/content/browser/renderer_host/media/render_frame_audio_output_stream_factory.cc
@@ -0,0 +1,117 @@
+// 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 "content/browser/renderer_host/media/render_frame_audio_output_stream_factory.h"
+
+#include <utility>
+
+#include "base/metrics/histogram_macros.h"
+#include "base/threading/thread_checker.h"
+#include "content/browser/bad_message.h"
+#include "content/browser/renderer_host/media/renderer_audio_output_stream_factory_context.h"
+#include "media/base/audio_parameters.h"
+#include "media/mojo/services/mojo_audio_output_stream_provider.h"
+#include "mojo/public/cpp/bindings/binding.h"
+
+namespace content {
+
+namespace {
+
+void UMALogDeviceAuthorizationTime(base::TimeTicks auth_start_time) {
+  UMA_HISTOGRAM_CUSTOM_TIMES("Media.Audio.OutputDeviceAuthorizationTime",
+                             base::TimeTicks::Now() - auth_start_time,
+                             base::TimeDelta::FromMilliseconds(1),
+                             base::TimeDelta::FromMilliseconds(5000), 50);
+}
+
+}  // namespace
+
+RenderFrameAudioOutputStreamFactory::RenderFrameAudioOutputStreamFactory(
+    RendererAudioOutputStreamFactoryContext* context,
+    int render_frame_id)
+    : context_(context), render_frame_id_(render_frame_id) {
+  DCHECK(thread_checker_.CalledOnValidThread());

[DaleCurtis, 2017/03/24 17:47:12]

Meaningless right? It's bound to the thread first used on.

[Max Morin, 2017/03/27 14:40:50]

Done.

+  DCHECK(context_);
+}
+
+RenderFrameAudioOutputStreamFactory::~RenderFrameAudioOutputStreamFactory() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+}

[DaleCurtis, 2017/03/24 17:47:12]

DCHECK(stream_providers_.empty()) ? Otherwise you may have dangling callbacks
holding unretained refs to this.

[Max Morin, 2017/03/27 14:40:50]

I changed this to explicitly clear |stream_providers_| (as intended, we don't
really have any guarantee that it's empty).

+
+void RenderFrameAudioOutputStreamFactory::RequestDeviceAuthorization(
+    media::mojom::AudioOutputStreamProviderRequest stream_provider_request,
+    int64_t session_id,
+    const std::string& device_id,
+    const url::Origin& origin,
+    const RequestDeviceAuthorizationCallback& callback) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  const base::TimeTicks auth_start_time = base::TimeTicks::Now();
+
+  if (!base::IsValueInRangeForNumericType<int>(session_id)) {
+    UMALogDeviceAuthorizationTime(auth_start_time);

[DaleCurtis, 2017/03/24 17:47:12]

We don't log this in the existing ARH, so it will skew metrics if you add it
here. Do we want that?

[Max Morin, 2017/03/27 14:40:50]

In practice, this branch will hopefully never happen, but I see your point, so I
removed it.

+    bad_message::ReceivedBadMessage(context_->GetRenderProcessId(),
+                                    bad_message::RFAOSF_OUT_OF_RANGE_INTEGER);
+    // Note: We must call the callback even though we are killing the renderer.
+    // This is mandated by mojo.
+    callback.Run(
+        media::OutputDeviceStatus::OUTPUT_DEVICE_STATUS_ERROR_NOT_AUTHORIZED,
+        media::AudioParameters::UnavailableDeviceParams(), std::string());
+    return;
+  }
+
+  context_->RequestDeviceAuthorization(
+      render_frame_id_, static_cast<int>(session_id), device_id, origin,

[DaleCurtis, 2017/03/24 17:47:12]

Hmm, why do we bother sending int64_t across if we only want an int? Are you
planning to change the message later to just be an int?

[Max Morin, 2017/03/27 14:40:50]

Since mojom files are cross-platform, we cannot use int (which is
platform-specific) in them, hence this ugly mess. It's rather silly :). I'd like
to get rid of session_id (the IPC interfaces returning session_id should return
an Audio(Output|Input)StreamProvider directly instead). Alternatively,
session_id could be an int32, UnguessableToken or some other fixed-width type.
But that is outside of the scope of this CL.

+      base::Bind(&RenderFrameAudioOutputStreamFactory::AuthorizationCompleted,
+                 base::Unretained(this), origin, auth_start_time,
+                 base::Passed(&stream_provider_request), callback));
+}
+
+void RenderFrameAudioOutputStreamFactory::AuthorizationCompleted(
+    const url::Origin& origin,
+    base::TimeTicks auth_start_time,
+    media::mojom::AudioOutputStreamProviderRequest request,
+    const RequestDeviceAuthorizationCallback& callback,
+    media::OutputDeviceStatus status,
+    bool should_send_id,
+    const media::AudioParameters& params,
+    const std::string& raw_device_id) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  UMALogDeviceAuthorizationTime(auth_start_time);
+
+  if (status != media::OUTPUT_DEVICE_STATUS_OK) {
+    callback.Run(media::OutputDeviceStatus(status),
+                 media::AudioParameters::UnavailableDeviceParams(),
+                 std::string());
+    return;
+  }
+
+  stream_providers_.push_back(
+      base::MakeUnique<media::MojoAudioOutputStreamProvider>(
+          std::move(request),
+          base::BindOnce(
+              &RendererAudioOutputStreamFactoryContext::CreateDelegate,
+              base::Unretained(context_), raw_device_id, render_frame_id_),
+          base::Bind(&RenderFrameAudioOutputStreamFactory::RemoveStream,
+                     base::Unretained(this))));

[DaleCurtis, 2017/03/24 17:47:12]

See note above; seems like this could lead to callbacks with bad refs.

[Max Morin, 2017/03/27 14:40:50]

I clarified the lifetime of all stream providers above.

+
+  callback.Run(media::OutputDeviceStatus(status), params,
+               should_send_id
+                   ? context_->GetHMACForDeviceId(origin, raw_device_id)
+                   : std::string());
+}
+
+void RenderFrameAudioOutputStreamFactory::RemoveStream(
+    media::mojom::AudioOutputStreamProvider* stream_provider) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  auto it = std::find_if(

[DaleCurtis, 2017/03/24 17:47:12]

base::EraseIf, if you want.

[Max Morin, 2017/03/27 14:40:50]

Done. Since I found flat_set, I also changed to using that so I can stop
reinventing the wheel :).

+      stream_providers_.begin(), stream_providers_.end(),
+      [stream_provider](
+          const std::unique_ptr<media::mojom::AudioOutputStreamProvider>&
+              other) { return other.get() == stream_provider; });
+  std::swap(*it, stream_providers_.back());
+  stream_providers_.pop_back();
+}
+
+}  // namespace content