media: Support creation and SetCdm() for mojo based CDM.

media/mojo/services/mojo_cdm_factory.h

 // Copyright 2014 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_CDM_DEFAULT_CDM_FACTORY_H_
-#define MEDIA_CDM_DEFAULT_CDM_FACTORY_H_
+#ifndef MEDIA_MOJO_SERVICES_MOJO_CDM_FACTORY_H_
+#define MEDIA_MOJO_SERVICES_MOJO_CDM_FACTORY_H_
 
 #include "base/macros.h"
 #include "media/base/cdm_factory.h"
+#include "media/mojo/interfaces/content_decryption_module_factory.mojom.h"
+#include "mojo/public/cpp/bindings/interface_impl.h"
 
 namespace media {
 
-class DefaultCdmFactory : public CdmFactory {
+class MojoCdmFactory : public CdmFactory {
  public:
-  DefaultCdmFactory();
-  ~DefaultCdmFactory() final;
+  explicit MojoCdmFactory(
+      mojo::ContentDecryptionModuleFactoryPtr remote_factory);
+  ~MojoCdmFactory() final;
 
   // CdmFactory implementation.
   scoped_ptr<MediaKeys> Create(
       const std::string& key_system,
       const GURL& security_origin,
       const SessionMessageCB& session_message_cb,
       const SessionClosedCB& session_closed_cb,
       const SessionErrorCB& session_error_cb,
       const SessionKeysChangeCB& session_keys_change_cb,
       const SessionExpirationUpdateCB& session_expiration_update_cb) final;
 
  private:
-  DISALLOW_COPY_AND_ASSIGN(DefaultCdmFactory);
+  // The next CDM ID for the current process.
+  static int next_cdm_id_;

[ddorwin, 2015/01/06 00:57:28]

See comment in .mojom.

This will not work when Mojo supports OOP clients and there is more than one
client process.

[xhwang, 2015/01/06 19:54:54]

The plan for supporting a dedicated CDM/media process is not clear yet. But no
matter what we do, we'll never mix the services for different processes, which
is not secure. So services for different render processes will be hosted in
different mojo application instances (or something similar), even though all
these instances may live in the same process.

This is similar to what we are doing in the browser process, where we have
RenderProcessHostImpl hosting mojo services for the corresponding render
process:
https://code.google.com/p/chromium/codesearch#chromium/src/content/browser/re...

With this, a unique per-process cdm_id should be safe to use.

[ddorwin, 2015/01/07 00:37:13]

I think what you mean is that there will also be a host ID/object that will be
dedicated to this client process, so the IDs will not be shared between clients.
Is that right?

+
+  mojo::ContentDecryptionModuleFactoryPtr remote_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(MojoCdmFactory);
 };
 
 }  // namespace media
 
-#endif  // MEDIA_CDM_DEFAULT_CDM_FACTORY_H_
+#endif  // MEDIA_MOJO_SERVICES_MOJO_CDM_FACTORY_H_