Add Promises for EME (Chromium side)

media/base/android/media_drm_bridge.h

Index: media/base/android/media_drm_bridge.h
diff --git a/media/base/android/media_drm_bridge.h b/media/base/android/media_drm_bridge.h
index 60b4dd898479e9a2adff44c3a54f2f0c18107810..7991d3a2af80e91fb61e8df56d3eb46c088d1e46 100644
--- a/media/base/android/media_drm_bridge.h
+++ b/media/base/android/media_drm_bridge.h
@@ -24,7 +24,7 @@ class MediaPlayerManager;
 
 // This class provides DRM services for android EME implementation.
 // TODO(qinmin): implement all the functions in this class.
-class MEDIA_EXPORT MediaDrmBridge : public MediaKeys {
+class MEDIA_EXPORT MediaDrmBridge {
  public:
   enum SecurityLevel {
     SECURITY_LEVEL_NONE = 0,
@@ -82,17 +82,16 @@ class MEDIA_EXPORT MediaDrmBridge : public MediaKeys {
   //   object. Calling this function multiples times may cause errors.
   bool SetSecurityLevel(SecurityLevel security_level);
 
-  // MediaKeys implementations.
-  virtual bool CreateSession(uint32 session_id,
-                             const std::string& content_type,
-                             const uint8* init_data,
-                             int init_data_length) OVERRIDE;
-  virtual void LoadSession(uint32 session_id,
-                           const std::string& web_session_id) OVERRIDE;
-  virtual void UpdateSession(uint32 session_id,
-                             const uint8* response,
-                             int response_length) OVERRIDE;
-  virtual void ReleaseSession(uint32 session_id) OVERRIDE;
+  // Media key operations.
+  bool CreateSession(uint32 session_id,
+                     const std::string& content_type,
+                     const uint8* init_data,
+                     int init_data_length);
+  void LoadSession(uint32 session_id, const std::string& web_session_id);
+  void UpdateSession(uint32 session_id,
+                     const uint8* response,
+                     int response_length);
+  void ReleaseSession(uint32 session_id);
 
   // Returns a MediaCrypto object if it's already created. Returns a null object
   // otherwise.