Have HTMLMediaElement::play() return a Promise.

third_party/WebKit/Source/core/dom/DOMException.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 63 matching lines @@
     { "PathExistsError", "An attempt was made to create a file or directory where an element already exists.", 0 },
 
     // SQL
     { "DatabaseError", "The operation failed for some reason related to the database.", 0 },
 
     // Web Crypto
     { "OperationError", "The operation failed for an operation-specific reason", 0 },
 
     // Push API
     { "PermissionDeniedError", "User or security policy denied the request.", 0 },
+
+    { "NotAllowedError", "The request is not allowed by the user agent or the platform in the current context.", 0 },

[philipj_slow, 2016/02/02 09:56:33]

Oh, somehow I failed to notice or just forgot that
https://github.com/heycam/webidl/pull/85 was still open.

Document that this was added for HTML and Media Session, assuming you agree with
using it for activate() also?

[philipj_slow, 2016/02/04 10:54:20]

Ping.

[mlamouri (slow - plz ping), 2016/02/18 17:06:06]

Done.

+
+    // Please add new entries at the end of this list to guarantee any ordering
+    // expectations.
 };
 
 static const CoreException* getErrorEntry(ExceptionCode ec)
 {
     size_t tableSize = WTF_ARRAY_LENGTH(coreExceptions);
     size_t tableIndex = ec - IndexSizeError;
 
     return tableIndex < tableSize ? &coreExceptions[tableIndex] : 0;
 }
 
@@ skipping 54 matching lines @@
 {
     const CoreException* entry = getErrorEntry(ec);
     ASSERT(entry);
     if (!entry)
         return "Unknown error.";
 
     return entry->message;
 }
 
 } // namespace blink