Add Promises for EME (Chromium side)

ppapi/api/private/pp_content_decryptor.idl

Index: ppapi/api/private/pp_content_decryptor.idl
diff --git a/ppapi/api/private/pp_content_decryptor.idl b/ppapi/api/private/pp_content_decryptor.idl
index 16be86edbf202f02cd1a09cc5021192b01ddd854..4493c3eab7aeed2dfdec80e3ed1014ab0a69b7d4 100644
--- a/ppapi/api/private/pp_content_decryptor.idl
+++ b/ppapi/api/private/pp_content_decryptor.idl
@@ -399,3 +399,26 @@ enum PP_DecryptorStreamType {
   PP_DECRYPTORSTREAMTYPE_AUDIO = 0,
   PP_DECRYPTORSTREAMTYPE_VIDEO = 1
 };
+
+/**
+ * <code>PP_SessionType</code> contains session type constants.
+ */
+[assert_size(4)]
+enum PP_SessionType {
+  PP_SESSIONTYPE_TEMPORARY = 0,
+  PP_SESSIONTYPE_PERSISTENT = 1
+};
+
+/**
+ * <code>PP_CdmExceptionCode</code> contains exception code constants.
+ */
+[assert_size(4)]
+enum PP_CdmExceptionCode {
+  PP_CDMEXCEPTIONCODE_NOTSUPPORTEDERROR = 1,
+  PP_CDMEXCEPTIONCODE_INVALIDSTATEERROR = 2,
+  PP_CDMEXCEPTIONCODE_INVALIDACCESSERROR = 3,
+  PP_CDMEXCEPTIONCODE_QUOTAEXCEEDEDERROR = 4,
+  PP_CDMEXCEPTIONCODE_UNKNOWNERROR = 5,
+  PP_CDMEXCEPTIONCODE_CLIENTERROR = 6,
+  PP_CDMEXCEPTIONCODE_OUTPUTERROR = 7
+};