Add OnDurationChange() to RenderClient

media/mojo/interfaces/renderer.mojom

Index: media/mojo/interfaces/renderer.mojom
diff --git a/media/mojo/interfaces/renderer.mojom b/media/mojo/interfaces/renderer.mojom
index f9cbee6a2acc697a1729b674d231169c7173150f..4b68de4d8fda6889999a751c96ea172b858b578a 100644
--- a/media/mojo/interfaces/renderer.mojom
+++ b/media/mojo/interfaces/renderer.mojom
@@ -69,4 +69,8 @@ interface RendererClient {
   // Called when the remote renderering service is waiting on the decryption
   // key.
   OnWaitingForDecryptionKey();
+
+  // Executed the first time the metadata is updated, and whenever the duration
+  // changes.
+  OnDurationChange(int64 duration_usec);
 };