[Clank] Implement MediaDrmStorageBridge with MediaDrmStorage

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 d86ee79511ef2caf2bddd83e776e781eea4dbb44..6dc26a4574cf3b89cf0d906dc9410adcd1746004 100644
--- a/media/base/android/media_drm_bridge.h
+++ b/media/base/android/media_drm_bridge.h
@@ -311,9 +311,6 @@ class MEDIA_EXPORT MediaDrmBridge : public ContentDecryptionModule,
   // The callback to create a ProvisionFetcher.
   CreateFetcherCB create_fetcher_cb_;
 
-  // The callback to create a MediaDrmStorage.
-  CreateStorageCB create_storage_cb_;
-
   // The ProvisionFetcher that requests and receives provisioning data.
   // Non-null iff when a provision request is pending.
   std::unique_ptr<ProvisionFetcher> provision_fetcher_;