Support for AudioContextOptions latencyHint.

third_party/WebKit/Source/modules/webaudio/AudioContextOptions.idl

Index: third_party/WebKit/Source/modules/webaudio/AudioContextOptions.idl
diff --git a/third_party/WebKit/Source/modules/webaudio/AudioContextOptions.idl b/third_party/WebKit/Source/modules/webaudio/AudioContextOptions.idl
new file mode 100644
index 0000000000000000000000000000000000000000..ffc2bef4bc7f22f46fe6734d8b9682227702e562
--- /dev/null
+++ b/third_party/WebKit/Source/modules/webaudio/AudioContextOptions.idl
@@ -0,0 +1,10 @@
+// Copyright 2016 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.
+
+typedef (AudioContextLatencyCategory or double) LatencyHint;
+
+// See https://webaudio.github.io/web-audio-api/#audiocontextoptions
+dictionary AudioContextOptions {
+    LatencyHint latencyHint = "interactive";

[Raymond Toy, 2016/12/08 17:14:38]

Does this introduce LatencyHint into the global namespace?  If so, that's
probably not something we want.

[Andrew MacPherson, 2016/12/09 12:34:14]

I believe it does. I've renamed it to AudioContextLatencyHint, does that work?
hongchan@ mentioned in a previous comment that having this typedef is the way to
ensure that the AudioContextLatencyCategoryOrDouble type is generated properly.

[Raymond Toy, 2016/12/13 15:53:11]

That would be unfortunate, I think.  In my original CL, I don't think I had to
to this.  AudioContextLatencyCategoryOrDouble was defined in the C++ code,
eventually.  I don't 
remember what I had to do to make this happen.  Or maybe I'm just wrong.

[Andrew MacPherson, 2016/12/14 09:07:20]

The original CL doesn't compile but I took another look here and you're right
that the typedef is not needed. This was my mistake, the part I believe I was
missing was that the type's .cpp/.h files needed to be included in
Source/bindings/modules/v8/generated.gni (they are now but weren't when I was
first looking at this). I've removed the typedef now, thanks!

+};