Add a function to convert key system into UUID

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 60ecfa14a9cf43443f3dad2ef688f76dcbe8e9ea..90f6d1349c73ba3ca6e772e37caaf69ef0319144 100644
--- a/media/base/android/media_drm_bridge.h
+++ b/media/base/android/media_drm_bridge.h
@@ -19,10 +19,13 @@ namespace media {
 // TODO(qinmin): implement all the functions in this class.
 class MEDIA_EXPORT MediaDrmBridge : public MediaKeys {
  public:
-  // TODO(xhwang): Pass in |key_system|.
-  MediaDrmBridge(int media_keys_id, const std::vector<uint8>& uuid);
   virtual ~MediaDrmBridge();
 
+  // Returns a MediaDrmBridge instance if |uuid| is supported, or a NULL
+  // pointer otherwise.
+  static MediaDrmBridge* Create(int media_keys_id,
+                                const std::vector<uint8>& uuid);
+
   // Checks whether DRM is available.
   static bool IsAvailable();
 
@@ -51,9 +54,14 @@ class MEDIA_EXPORT MediaDrmBridge : public MediaKeys {
   int media_keys_id() const { return media_keys_id_; }
 
  private:
+  MediaDrmBridge(int media_keys_id, const std::vector<uint8>& uuid);
+
   // Id of the MediaKeys object.
   int media_keys_id_;
 
+  // UUID of the key system.
+  std::vector<uint8> uuid_;
+
   DISALLOW_COPY_AND_ASSIGN(MediaDrmBridge);
 };