Make item and namedItem args in MimeTypeArray/PluginArray/Plugin non-optional

third_party/WebKit/Source/modules/plugins/Plugin.idl

Index: third_party/WebKit/Source/modules/plugins/Plugin.idl
diff --git a/third_party/WebKit/Source/modules/plugins/Plugin.idl b/third_party/WebKit/Source/modules/plugins/Plugin.idl
index f8db9816fe2f1583fd1c1f6090767385c957780a..a325a6bea7765872feb3824f22b64fb7c9555889 100644
--- a/third_party/WebKit/Source/modules/plugins/Plugin.idl
+++ b/third_party/WebKit/Source/modules/plugins/Plugin.idl
@@ -27,7 +27,7 @@
     readonly attribute DOMString filename;
     readonly attribute DOMString description;
     readonly attribute unsigned long length;
-    getter MimeType? item([Default=Undefined] optional unsigned long index);
-    MimeType? namedItem([Default=Undefined] optional DOMString name);
-    [NotEnumerable, ImplementedAs=namedItem] getter MimeType ([Default=Undefined] optional DOMString name);
+    getter MimeType? item(unsigned long index);
+    [NotEnumerable] getter MimeType? namedItem(DOMString name);

[foolip, 2017/03/21 08:57:52]

Adding [NotEnumerable] here should change the enumerability of the namedItem
method, which we don't want. I don't know why [NotEnumerable] was used
originally below, but just omitting should be fine, because by definition an
anonymous getter doesn't have a name to enumerate.

[lunalu1, 2017/03/21 17:56:50]

I tried to do it without NotEnumerable, but the generated code was changed and
also
required additional implementation of namedPRopertyQuery and
namedPropertyEnumerator.
LegacyUnenumerableNamedProperties suggests that named properties shouldn't be
enumerable:
https://heycam.github.io/webidl/#LegacyUnenumerableNamedProperties

[foolip, 2017/03/22 05:04:52]

Ah, I missed the [LegacyUnenumerableNamedProperties] on the interface level.
https://software.hixie.ch/utilities/js/live-dom-viewer/?saved=4962 shows that
the namedItem name is enumerable, so adding [NotEnumerable] here would change
that.

I guess the only choice is to remove [NotEnumerable] here and to keep the second
line for now, exception the argument doesn't need to be optional.

I filed https://bugs.chromium.org/p/chromium/issues/detail?id=703990, can you
add a TODO to use it here?

[lunalu1, 2017/03/24 15:42:17]

"If the [LegacyUnenumerableNamedProperties] extended attribute appears on a
interface that supports named properties, it indicates that all the interface’s
named properties are unenumerable"?

Our WebIDL compiler indicates that by an attribute on the named property getter
rather than one on the interface. But isn't it functionally equivalent?

[foolip, 2017/03/30 04:52:21]

Not entirely, it seems like [NotEnumerable] also suppresses the generation of a
namedPropertyQuery call, which I think should still work even if things aren't
enumerable.

[lunalu1, 2017/03/30 18:32:03]

I see. I guess for now we will just keep both the getter and the the method.

+    // [NotEnumerable, ImplementedAs=namedItem] getter MimeType ([Default=Undefined] optional DOMString name);

[foolip, 2017/03/21 08:57:52]

Remove this line rather than commenting it out.

 };