Removes Nexus 6 from OpenSL ES blacklist.

BUG=b/1370703002
R=magjed@webrtc.org

Review URL: https://codereview.webrtc.org/1370703002 .

Cr-Commit-Position: refs/heads/master@{#10077}

webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine/WebRtcAudioManager.java

@@ -113,8 +113,6 @@ class WebRtcAudioManager {
     boolean blacklisted =
         WebRtcAudioUtils.deviceIsBlacklistedForOpenSLESUsage();
     if (blacklisted) {
-      // TODO(henrika): enable again for all devices once issue in b/21485703
-      // has been resolved.
       Logging.e(TAG, Build.MODEL + " is blacklisted for OpenSL ES usage!");
     }
     return blacklisted;

webrtc/modules/audio_device/android/java/src/org/webrtc/voiceengine/WebRtcAudioUtils.java

@@ -33,7 +33,7 @@ public final class WebRtcAudioUtils {
   // the low latency output mode in combination with OpenSL ES.
   // The device name is given by Build.MODEL.
   private static final String[] BLACKLISTED_OPEN_SL_ES_MODELS = new String[] {
-      "Nexus 6", // Nexus 6
+    // This list is currently empty ;-)
   };
 
   // List of devices where it has been verified that the built-in effect