Add audible, muted to Tab, c.t.query, c.t.update, and c.t.onUpdated where relevant

chrome/test/data/extensions/api_test/tabs/basics/sinewave.js

+var freqs = [200, 500, 1800];
+var curTestIdx = 0;
+if (!this.audioContext) {
+  this.audioContext = new AudioContext();
+  this.gainNode = this.audioContext.createGain();
+  this.gainNode.gain.value = 0.5;
+  this.gainNode.connect(this.audioContext.destination);
+}
+if (!this.oscillator ||
+    this.oscillator.frequency.value != freqs[curTestIdx]) {
+  // Note: We recreate the oscillator each time because this switches the
+  // audio frequency immediately.  Re-using the same oscillator tends to take
+  // several hundred milliseconds to ramp-up/down the frequency.
+  if (this.oscillator) {
+    this.oscillator.stop();
+    this.oscillator.disconnect();
+  }
+  this.oscillator = this.audioContext.createOscillator();
+  this.oscillator.type = OscillatorNode.SINE;
+  this.oscillator.frequency.value = freqs[curTestIdx];
+  this.oscillator.connect(this.gainNode);
+  this.oscillator.start();
+}