Add MediaError.message

third_party/WebKit/Source/core/html/media/MediaError.h

 /*
  * Copyright (C) 2007 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 11 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef MediaError_h
 #define MediaError_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "core/CoreExport.h"
 #include "platform/heap/Handle.h"
+#include "platform/wtf/text/WTFString.h"
 
 namespace blink {
 
-class CORE_EXPORT MediaError final : public GarbageCollected<MediaError>,
-                                     public ScriptWrappable {
+class CORE_EXPORT MediaError final
+    : public GarbageCollectedFinalized<MediaError>,

[mlamouri (slow - plz ping), 2017/04/21 10:26:24]

Why Finalized? Finalized adds an overhead for the GC so we should avoid this
unless there is a reason for it.

[wolenetz, 2017/04/21 10:47:00]

WTFString has a RefPtr private member, which IIUC requires that classes that
have a WTFString themselves require finalization (which the message_ added in
this CL to MediaError triggers). See
https://chromium.googlesource.com/chromium/src/+/master/third_party/WebKit/So...

Also, when attempting to build with just GarbageCollected, the following error
occurred:
In file included from gen/blink/bindings/core/v8/V8MediaError.cpp:12: In file
included from gen/blink/bindings/core/v8/V8MediaError.h:23:
../../third_party/WebKit/Source/core/html/media/MediaError.h:36:1: error:
[blink-gc] Class 'MediaError' requires finalization.

tl;dr: As we chatted about just now, I think GarbageCollectedFinalized is needed
here.

+      public ScriptWrappable {
   DEFINE_WRAPPERTYPEINFO();
 
  public:
   enum ErrorCode {
     kMediaErrAborted = 1,
     kMediaErrNetwork,
     kMediaErrDecode,
     kMediaErrSrcNotSupported,
   };
 
-  static MediaError* Create(ErrorCode code) { return new MediaError(code); }
+  static MediaError* Create(ErrorCode code, const String& message) {
+    return new MediaError(code, message);
+  }
 
   ErrorCode code() const { return code_; }
 
+  // Returns either an empty string, or a human readable string describing
+  // additional error detail.
+  String message() const { return message_; }
+
   DEFINE_INLINE_TRACE() {}
 
  private:
-  MediaError(ErrorCode code) : code_(code) {}
+  MediaError(ErrorCode code, const String& message)
+      : code_(code), message_(message) {}
 
   ErrorCode code_;
+  String message_;
 };
 
 }  // namespace blink
 
 #endif  // MediaError_h