Update comment to use kInitializationError

kSessionError has been replaced by kInitializationError. Update comments
to reflect this.

Credit to hmchen@ who found this.

Change-Id: I9be2142a932223d571496ac37988159fc2e41edc
diff --git a/content_decryption_module.h b/content_decryption_module.h
index 3f06501..46cfa18 100644
--- a/content_decryption_module.h
+++ b/content_decryption_module.h
@@ -799,8 +799,8 @@
   //
   // Returns kSuccess if the |audio_decoder_config| is supported and the CDM
   // audio decoder is successfully initialized.
-  // Returns kSessionError if |audio_decoder_config| is not supported. The CDM
-  // may still be able to do Decrypt().
+  // Returns kInitializationError if |audio_decoder_config| is not supported.
+  // The CDM may still be able to do Decrypt().
   // Returns kDeferredInitialization if the CDM is not ready to initialize the
   // decoder at this time. Must call Host::OnDeferredInitializationDone() once
   // initialization is complete.
@@ -812,8 +812,8 @@
   //
   // Returns kSuccess if the |video_decoder_config| is supported and the CDM
   // video decoder is successfully initialized.
-  // Returns kSessionError if |video_decoder_config| is not supported. The CDM
-  // may still be able to do Decrypt().
+  // Returns kInitializationError if |video_decoder_config| is not supported.
+  // The CDM may still be able to do Decrypt().
   // Returns kDeferredInitialization if the CDM is not ready to initialize the
   // decoder at this time. Must call Host::OnDeferredInitializationDone() once
   // initialization is complete.