Gate available() and install() behind a policy (#164)

* Gate available() and install() behind a policy

* Gate available() and install() behind a policy

---------

Co-authored-by: Evan Liu <[email protected]>

Author: evanbliu

index.bs

@@ -383,6 +383,7 @@ See <a href="https://lists.w3.org/Archives/Public/public-speech-api/2012Sep/0072
   <dt><dfn method for=SpeechRecognition>available({{SpeechRecognitionOptions}} options)</dfn> method</dt>
   <dd>
     The {{SpeechRecognition/available}} method returns a {{Promise}} that resolves to a {{AvailabilityStatus}} indicating the recognition availability matching the {{SpeechRecognitionOptions}} argument.
+    Access to this method is gated behind the [=policy-controlled feature=] "on-device-speech-recognition", which has a [=policy-controlled feature/default allowlist=] of <code>[=default allowlist/'self'=]</code>.
 
     When invoked, run these steps:
     1. Let <var>promise</var> be <a>a new promise</a>.
@@ -396,6 +397,7 @@ See <a href="https://lists.w3.org/Archives/Public/public-speech-api/2012Sep/0072
     It returns a {{Promise}} that resolves to a {{boolean}}.
     The promise resolves to `true` when all installation attempts for requested and supported languages succeed (or the languages were already installed).
     The promise resolves to `false` if `options.langs` is empty, if not all of the requested languages are supported, or if any installation attempt for a supported language fails.
+    Access to this method is gated behind the [=policy-controlled feature=] "on-device-speech-recognition", which has a [=policy-controlled feature/default allowlist=] of <code>[=default allowlist/'self'=]</code>.
 
     When invoked, run these steps:
     1. If the [=current settings object=]'s [=relevant global object=]'s [=associated Document=] is NOT [=fully active=], throw an {{InvalidStateError}} and abort these steps.