Media Remoting: Add remoting control logic for encrypted contents.

media/remoting/remoting_cdm_controller.h

+// 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.
+
+#ifndef MEDIA_REMOTING_REMOTING_CDM_CONTROLLER_H_
+#define MEDIA_REMOTING_REMOTING_CDM_CONTROLLER_H_
+
+#include "base/callback.h"
+#include "base/memory/weak_ptr.h"
+#include "media/remoting/remoting_source_impl.h"
+
+namespace base {
+class ThreadChecker;
+}

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

This won't work and you are actually getting the declaration of ThreadChecker
from remoting_source_impl.h. Please remove this forward declaration and add
include directly.

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

Done.

+
+namespace media {
+
+// This class controlls whether to start a remoting session to create CDM.
+// The |remoting_source_| will be passed to the RemotingRendererController when
+// the CDM is attached to a media element.
+class RemotingCdmController final : public RemotingSourceImpl::Client {
+ public:
+  explicit RemotingCdmController(
+      scoped_refptr<RemotingSourceImpl> remoting_source);
+  ~RemotingCdmController();
+
+  // RemotingSourceImpl::Client implementations.
+  void OnStarted(bool success) override;
+  void OnSessionStateChanged() override;
+
+  // Query whether to create a Media Remoting CDM. |cb| could be run
+  // synchronously or asynchronously, depending on whether the required
+  // information is available now or later.
+  using CdmCheckCallback = base::Callback<void(bool is_remoting)>;

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

nit: Returns whether we should create remoting CDM via |cb|, which could be run
synchronously .....

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

Done.

+  void ShouldCreateRemotingCdm(const CdmCheckCallback& cb);
+
+  RemotingSourceImpl* remoting_source() const {
+    DCHECK(thread_checker_.CalledOnValidThread());
+    return remoting_source_.get();

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

See comment above... why are we passing raw pointers to a ref-counted object
around?

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

See reply above. :)

+  }
+
+ private:
+  const scoped_refptr<RemotingSourceImpl> remoting_source_;
+
+  // This callback is run once to report whether to create remoting CDM.
+  CdmCheckCallback cdm_check_cb_;
+
+  // Indicates if remoting is started.

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

what does "remoting is started" means exactly? e.g. remoting CDM created?

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

This variable indicates if in remoting. i.e., remoting session is started.
Modified the comment.

+  bool is_remoting_ = false;
+
+  // This is used to check all the methods are called on the current thread in
+  // debug builds.

[xhwang, 2016/11/01 08:21:28]

nit: This comment seems unnecessary :) But it's up to you.

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

Done.

+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(RemotingCdmController);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_REMOTING_REMOTING_CDM_CONTROLLER_H_