Media Remoting: Add remoting control logic for encrypted contents.

media/remoting/remoting_renderer_controller.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 "media/remoting/remoting_renderer_controller.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/threading/thread_checker.h"
+#include "media/remoting/remoting_cdm.h"
+
+namespace media {
+
+RemotingRendererController::RemotingRendererController(

[xhwang, 2016/11/01 08:21:29]

For future CL, please consider do renames in a separate CL. Rename CLs will be
super trivial to review, then this CL will be much less noisy.

If you have to do renames in the same CL, please consider upload a rename-only
patchset first, then upload real changes in a different patchset. This way,
it'll be much easier to see the real changes by looking at patchset differences.

Now for this file, it's pretty hard to know what has been changed. I can get a
better view by looking at the diff against PS1, but PS1 may already contain
other changes (since it's PS4 in the previous CL).

[xjz, 2016/11/01 21:55:53]

Acknowledged.

+    scoped_refptr<RemotingSourceImpl> remoting_source)
+    : remoting_source_(remoting_source), weak_factory_(this) {
+  remoting_source_->AddClient(this);
+}
+
+RemotingRendererController::~RemotingRendererController() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  remoting_source_->RemoveClient(this);
+}
+
+void RemotingRendererController::OnStarted(bool success) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (success) {
+    VLOG(1) << "Remoting started successively.";
+    if (remote_rendering_started_) {
+      DCHECK(!switch_renderer_cb_.is_null());
+      switch_renderer_cb_.Run();
+    } else {
+      remoting_source_->StopRemoting(this);
+    }
+  } else {
+    VLOG(1) << "Failed to start remoting.";
+    remote_rendering_started_ = false;
+  }
+}
+
+void RemotingRendererController::OnSessionStateChanged() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  VLOG(1) << "OnSessionStateChanged: " << remoting_source_->state();
+  UpdateAndMaybeSwitch();
+}
+
+void RemotingRendererController::OnEnteredFullscreen() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  is_fullscreen_ = true;
+  UpdateAndMaybeSwitch();
+}
+
+void RemotingRendererController::OnExitedFullscreen() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  is_fullscreen_ = false;
+  UpdateAndMaybeSwitch();
+}
+
+void RemotingRendererController::OnSetCdm(CdmContext* cdm_context) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  auto* cdm = RemotingCdm::From(cdm_context);

[xhwang, 2016/11/01 08:21:29]

Is GetRemotingSource() the only thing you need from the CDM? The purpose that we
have CdmContext is to isolate the media player (e.g. renderer) from accessing
the CDM directly. Therefore, it's more desirable that we cast CdmContext to a
RemotingCdmContext here, and get GetRemotingSource() there, instead of getting
the CDM from the context, which defies the purpose of CdmContext.

You can see MediaDrmBridgeCdmContext for an example.

[xjz, 2016/11/01 21:55:53]

Done.

+  if (!cdm)
+    return;
+
+  remoting_source_->RemoveClient(this);
+  remoting_source_ = cdm->GetRemotingSource();
+  remoting_source_->AddClient(this);  // Calls OnSessionStateChanged().
+  UpdateAndMaybeSwitch();
+}
+
+void RemotingRendererController::SetSwitchRendererCallback(
+    const base::Closure& cb) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(!cb.is_null());
+
+  switch_renderer_cb_ = cb;
+  UpdateAndMaybeSwitch();
+}
+
+void RemotingRendererController::OnMetadataChanged(
+    const PipelineMetadata& metadata) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  has_video_ =
+      metadata.has_video && metadata.video_decoder_config.IsValidConfig();
+  has_audio_ =
+      metadata.has_audio && metadata.audio_decoder_config.IsValidConfig();
+
+  is_encrypted_ = false;
+  if (has_video_) {
+    video_decoder_config_ = metadata.video_decoder_config;
+    is_encrypted_ |= video_decoder_config_.is_encrypted();
+  }
+  if (has_audio_) {
+    audio_decoder_config_ = metadata.audio_decoder_config;
+    is_encrypted_ |= audio_decoder_config_.is_encrypted();
+  }
+  UpdateAndMaybeSwitch();
+}
+
+bool RemotingRendererController::IsVideoCodecSupported() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(has_video_);
+
+  switch (video_decoder_config_.codec()) {
+    case VideoCodec::kCodecH264:
+    case VideoCodec::kCodecVP8:
+      return true;
+    default:
+      VLOG(2) << "Remoting does not support video codec: "
+              << video_decoder_config_.codec();
+      return false;
+  }
+}
+
+bool RemotingRendererController::IsAudioCodecSupported() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(has_audio_);
+
+  switch (audio_decoder_config_.codec()) {
+    case AudioCodec::kCodecAAC:
+    case AudioCodec::kCodecMP3:
+    case AudioCodec::kCodecPCM:
+    case AudioCodec::kCodecVorbis:
+    case AudioCodec::kCodecFLAC:
+    case AudioCodec::kCodecAMR_NB:
+    case AudioCodec::kCodecAMR_WB:
+    case AudioCodec::kCodecPCM_MULAW:
+    case AudioCodec::kCodecGSM_MS:
+    case AudioCodec::kCodecPCM_S16BE:
+    case AudioCodec::kCodecPCM_S24BE:
+    case AudioCodec::kCodecOpus:
+    case AudioCodec::kCodecEAC3:
+    case AudioCodec::kCodecPCM_ALAW:
+    case AudioCodec::kCodecALAC:
+    case AudioCodec::kCodecAC3:
+      return true;
+    default:
+      VLOG(2) << "Remoting does not support audio codec: "
+              << audio_decoder_config_.codec();
+      return false;
+  }
+}
+
+bool RemotingRendererController::ShouldBeRemoting() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (switch_renderer_cb_.is_null())
+    return false;  // No way to switch to a RemotingRenderImpl.
+
+  const RemotingSessionState state = remoting_source_->state();
+  if (is_encrypted_) {
+    // Due to technical limitations when playing encrypted content, once a
+    // remoting session has been started, always return true here to indicate
+    // that the RemotingRendererImpl should be used. In the stopped states,
+    // RemotingRendererImpl will display an interstitial to notify the user that
+    // local rendering cannot be resumed.
+    return state == RemotingSessionState::SESSION_STARTED ||
+           state == RemotingSessionState::SESSION_STOPPING ||
+           state == RemotingSessionState::SESSION_PERMANENTLY_STOPPED;
+  }
+
+  switch (state) {
+    case SESSION_UNAVAILABLE:
+      return false;  // Cannot remote media without a remote sink.
+    case SESSION_CAN_START:
+    case SESSION_STARTING:
+    case SESSION_STARTED:
+      break;  // Media remoting is possible, assuming other requirments are met.
+    case SESSION_STOPPING:
+    case SESSION_PERMANENTLY_STOPPED:
+      return false;  // Use local rendering after stopping remoting.
+  }
+  if ((!has_audio_ && !has_video_) ||
+      (has_video_ && !IsVideoCodecSupported()) ||
+      (has_audio_ && !IsAudioCodecSupported()))
+    return false;
+
+  // Normally, entering fullscreen is the signal that starts remote rendering.
+  // However, current technical limitations require encrypted content be remoted
+  // without waiting for a user signal.
+  return is_fullscreen_;
+}
+
+void RemotingRendererController::UpdateAndMaybeSwitch() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  bool should_be_remoting = ShouldBeRemoting();
+
+  if (remote_rendering_started_ == should_be_remoting)
+    return;
+
+  // Switch between local renderer and remoting renderer.
+  remote_rendering_started_ = should_be_remoting;
+
+  if (remote_rendering_started_) {
+    DCHECK(!switch_renderer_cb_.is_null());
+    if (remoting_source_->state() ==
+        RemotingSessionState::SESSION_PERMANENTLY_STOPPED) {
+      switch_renderer_cb_.Run();
+      return;
+    }
+    // |switch_renderer_cb_.Run()| will be called after remoting is started
+    // successfully.
+    remoting_source_->StartRemoting(this);
+  } else {
+    // For encrypted content, it's only valid to switch to remoting renderer,
+    // and never back to the local renderer. The RemotingCdmController will
+    // force-stop the session when remoting has ended; so no need to call
+    // StopRemoting() from here.
+    DCHECK(!is_encrypted_);
+    switch_renderer_cb_.Run();
+    remoting_source_->StopRemoting(this);
+  }
+}
+
+}  // namespace media