Add Promises for EME (Chromium side)

media/base/browser_cdm.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_BASE_BROWSER_CDM_H_
 #define MEDIA_BASE_BROWSER_CDM_H_
 
 #include "media/base/media_keys.h"
 #include "media/base/player_tracker.h"
 
 namespace media {
 
 // Interface for browser side CDMs.
-class BrowserCdm : public MediaKeys, public PlayerTracker {
+class BrowserCdm : public PlayerTracker {
  public:
+  // TODO(jrummell): Update this to actually derive from MediaKeys
+  // (Use web_session_id rather than session_id).
+  typedef base::Callback<
+      void(uint32 session_id, const std::string& web_session_id)>
+      SessionCreatedCB;
+
+  typedef base::Callback<void(uint32 session_id,
+                              const std::vector<uint8>& message,
+                              const GURL& destination_url)> SessionMessageCB;
+
+  typedef base::Callback<void(uint32 session_id)> SessionReadyCB;
+
+  typedef base::Callback<void(uint32 session_id)> SessionClosedCB;
+
+  typedef base::Callback<void(uint32 session_id,
+                              media::MediaKeys::KeyError error_code,
+                              uint32 system_code)> SessionErrorCB;
+
   virtual ~BrowserCdm();
 
-  // MediaKeys implementation.
+  // MediaKeys-like implementation.
   virtual bool CreateSession(uint32 session_id,
                              const std::string& content_type,
                              const uint8* init_data,
                              int init_data_length) = 0;
   virtual void LoadSession(uint32 session_id,
                            const std::string& web_session_id) = 0;
   virtual void UpdateSession(uint32 session_id,
                              const uint8* response,
                              int response_length) = 0;
   virtual void ReleaseSession(uint32 session_id) = 0;
 
   // PlayerTracker implementation.
   virtual int RegisterPlayer(const base::Closure& new_key_cb,
                              const base::Closure& cdm_unset_cb) = 0;
   virtual void UnregisterPlayer(int registration_id) = 0;
 
  protected:
    BrowserCdm();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(BrowserCdm);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_BROWSER_CDM_H_