media: Hook up ContentDecryptionModuleClient in mojo CDM service.

media/mojo/interfaces/content_decryption_module.mojom

Index: media/mojo/interfaces/content_decryption_module.mojom
diff --git a/media/mojo/interfaces/content_decryption_module.mojom b/media/mojo/interfaces/content_decryption_module.mojom
index ba544e2800b77fb8427e06912cef5a78caa17a20..d6949f4461a7041cce051e1cf628cd7f9f604a6a 100644
--- a/media/mojo/interfaces/content_decryption_module.mojom
+++ b/media/mojo/interfaces/content_decryption_module.mojom
@@ -67,6 +67,9 @@ interface ContentDecryptionModule {
     PERSISTENT_RELEASE_MESSAGE_SESSION
   };
 
+  // Sets ContentDecryptionModuleClient. Must be called before any other calls.
+  SetClient(ContentDecryptionModuleClient client);
+
   // Provides a server certificate to be used to encrypt messages to the
   // license server.
   SetServerCertificate(array<uint8> certificate_data)