media: Use native BufferingState in media mojo interfaces

media/mojo/services/mojo_renderer_service.cc

Index: media/mojo/services/mojo_renderer_service.cc
diff --git a/media/mojo/services/mojo_renderer_service.cc b/media/mojo/services/mojo_renderer_service.cc
index bf6846834d95dbb7b056f9a2ef4153ad124f5676..50f6e56f82a4933070becdc9dd1553580e1e3632 100644
--- a/media/mojo/services/mojo_renderer_service.cc
+++ b/media/mojo/services/mojo_renderer_service.cc
@@ -165,7 +165,7 @@ void MojoRendererService::OnStatisticsUpdate(const PipelineStatistics& stats) {
 
 void MojoRendererService::OnBufferingStateChange(BufferingState state) {
   DVLOG(2) << __FUNCTION__ << "(" << state << ")";
-  client_->OnBufferingStateChange(static_cast<mojom::BufferingState>(state));
+  client_->OnBufferingStateChange(state);
 }
 
 void MojoRendererService::OnWaitingForDecryptionKey() {