Prime speech synthesis on microphone button click

[compulim]

Fix #2245, fix #1514, fix #1515.

Changelog Entry

• Fix #2245. Fix speech synthesis not working on Safari by priming the engine on the first microphone button click, by @compulim in PR #2246
• Fix #1514. Added reference grammar ID when using Cognitive Services Speech Services, by @compulim in PR #2246
• Fix #1515. Added dynamic phrases when using Cognitive Services Speech Services, by @compulim in PR #2246

Description

The AudioContext instance need to be primed by user gesture on Safari on iPad. Otherwise, audio clip playback will be paused indefinitely.

Also, dynamic phrases and reference grammar ID is added after bumping to latest web-speech-cognitive-services. Although dynamic phrases is supported, it is not used because currently, there are no fields in activity that provide suggestions or expected phrases.

Specific Changes

When the user click on the microphone button, we will prime the speech synthesis engine by sending an empty utterance.

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• Testing Added
• Bump web-speech-cognitive-services, it is required for a persistent and prime-able AudioContext object, in their PR #36

[coveralls]

Coverage increased (+0.1%) to 65.704% when pulling b530818 on compulim:fix-2245 into cac4cdb on microsoft:master.

[compulim]

Should bump to latest build and fix tests.