script: Fix audio-tuning frontend for web audio element name

webkitAudioContext is renamed to AudioContext.
webkitOfflineAudioContext is renamed to OfflineAudioContext.
createGainNode in AudioConext is renamed to createGain.
This CL fixes those element names so the site can work with both old and
new version.

Signed-off-by: Cheng-Yi Chiang <cychiang@chromium.org>

BUG=chromium:365989
TEST=run audio-tuning site on ubuntu desktop and chromeos

Change-Id: Icd18cac04e7db9549c5d307e21bfde8ab764bcfe
Reviewed-on: https://chromium-review.googlesource.com/196469
Reviewed-by: Chih-Chung Chang <chihchung@chromium.org>
Reviewed-by: Hsinyu Chao <hychao@chromium.org>
Commit-Queue: Cheng-Yi Chiang <cychiang@chromium.org>
Tested-by: Cheng-Yi Chiang <cychiang@chromium.org>

1 files changed, 22 insertions, 4 deletions

diff --git a/scripts/audio_tuning/frontend/audio.js b/scripts/audio_tuning/frontend/audio.js
index 5316c45c..08a2091d 100644
--- a/scripts/audio_tuning/frontend/audio.js
+++ b/scripts/audio_tuning/frontend/audio.js
@@ -118,8 +118,21 @@ var analyzer_right;     /* The FFT analyzer for right channel */
  * This value is stored in drc.emphasis_disabled in the config. */
 var browser_emphasis_disabled_detection_result;
 
+/* The supported audio element names are different on browsers with different
+ * versions.*/
+function fix_audio_elements() {
+  try {
+    window.AudioContext = window.AudioContext || window.webkitAudioContext;
+    window.OfflineAudioContext = (window.OfflineAudioContext ||
+        window.webkitOfflineAudioContext);
+  }
+  catch(e) {
+    alert('Web Audio API is not supported in this browser');
+  }
+}
+
 function init_audio() {
-  audioContext = new webkitAudioContext();
+  audioContext = new AudioContext();
   nyquist = audioContext.sampleRate / 2;
 }
 
@@ -599,9 +612,8 @@ function get_emphasis_disabled() {
   }
 
   function runTest() {
-
-    context = new webkitOfflineAudioContext(1, sampleRate * lengthInSeconds,
-                                            sampleRate);
+    context = new OfflineAudioContext(1, sampleRate * lengthInSeconds,
+                                      sampleRate);
     // Connect an oscillator to a gain node to the compressor.  The
     // oscillator frequency is set to a high value for the (original)
     // emphasis to kick in. The gain is a little extra boost to get the
@@ -627,6 +639,11 @@ function get_emphasis_disabled() {
 /* Returns one DRC filter */
 function drc() {
   var comp = audioContext.createDynamicsCompressor();
+
+  /* The supported method names are different on browsers with different
+   * versions.*/
+  audioContext.createGainNode = (audioContext.createGainNode ||
+                                 audioContext.createGain);
   var boost = audioContext.createGainNode();
   comp.threshold.value = INIT_DRC_THRESHOLD;
   comp.knee.value = INIT_DRC_KNEE;
@@ -1419,6 +1436,7 @@ function global_section(parent) {
 }
 
 window.onload = function() {
+  fix_audio_elements();
   /* Detects if emphasis is disabled and sets
    * browser_emphasis_disabled_detection_result. */
   get_emphasis_disabled();