MSE: Implement TrackDefaultList object

Source/modules/mediasource/TrackDefaultList.idl

Index: Source/modules/mediasource/TrackDefaultList.idl
diff --git a/Source/modules/mediasource/TrackDefaultList.idl b/Source/modules/mediasource/TrackDefaultList.idl
new file mode 100644
index 0000000000000000000000000000000000000000..ee822b6fcbf7ee47110afc1e3abf1ebb8d4e1a0c
--- /dev/null
+++ b/Source/modules/mediasource/TrackDefaultList.idl
@@ -0,0 +1,16 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Per 18 Nov 2014 Editor's Draft
+// https://w3c.github.io/media-source/#trackdefaultlist
+
+[
+    Constructor(sequence<TrackDefault> trackDefaults),
+    RaisesException=Constructor,
+    GarbageCollected,
+    RuntimeEnabled=MediaSourceExperimental,
+] interface TrackDefaultList {
+    readonly attribute unsigned long length;
+    [ImplementedAs=item] getter TrackDefault (unsigned long index);

[haraken, 2014/12/16 01:19:37]

Do we need [ImplementedAs=item]? I guess a getter that takes 'unsigned'
parameter should be recognized as an indexed getter (and thus is redirected to
item()) by default.

[wolenetz, 2014/12/16 19:29:44]

Yes, we need that annotation. Otherwise, the getter would need to be named
"anonymousIndexedGetter" in the implementation. I prefer explicit indication in
idl for readability.
Note, with that annotation removed, build fails:
 In file included from
gen/blink/bindings/modules/v8/V8GeneratedModulesBindings11.cpp:32:
 gen/blink/bindings/modules/v8/V8TrackDefaultList.cpp:73:41: error: no member
named 'anonymousIndexedGetter' in 'blink::TrackDefaultList'
     RawPtr<TrackDefault> result = impl->anonymousIndexedGetter(index);
                                  ~~~~  ^

+};