media: Make MediaKeys ref-counted.

media/cdm/proxy_decryptor.h

Index: media/cdm/proxy_decryptor.h
diff --git a/media/cdm/proxy_decryptor.h b/media/cdm/proxy_decryptor.h
index c7f60b94d3692196ab0d2ab0ef6a57196d61d170..8d4d2b862c6990746d27954fe60911d046082282 100644
--- a/media/cdm/proxy_decryptor.h
+++ b/media/cdm/proxy_decryptor.h
@@ -77,7 +77,7 @@ class MEDIA_EXPORT ProxyDecryptor {
   void OnCdmCreated(const std::string& key_system,
                     const GURL& security_origin,
                     const CdmContextReadyCB& cdm_context_ready_cb,
-                    scoped_ptr<MediaKeys> cdm,
+                    const scoped_refptr<MediaKeys>& cdm,
                     const std::string& error_message);
 
   void GenerateKeyRequestInternal(EmeInitDataType init_data_type,
@@ -129,7 +129,7 @@ class MEDIA_EXPORT ProxyDecryptor {
   bool is_creating_cdm_;
 
   // The real MediaKeys that manages key operations for the ProxyDecryptor.
-  scoped_ptr<MediaKeys> media_keys_;
+  scoped_refptr<MediaKeys> media_keys_;
 
 #if defined(OS_CHROMEOS) || defined(OS_ANDROID)
   MediaPermission* media_permission_;