Removed double-special-casing of ISAC in libjingle and WebRtcVoE.

webrtc/media/engine/webrtcvoiceengine.cc

Index: webrtc/media/engine/webrtcvoiceengine.cc
diff --git a/webrtc/media/engine/webrtcvoiceengine.cc b/webrtc/media/engine/webrtcvoiceengine.cc
index c23084eed113a55a1729922fb7e9f20afbde8b38..55adfce135898909463f3c36da6a4c0ec7a57e14 100644
--- a/webrtc/media/engine/webrtcvoiceengine.cc
+++ b/webrtc/media/engine/webrtcvoiceengine.cc
@@ -371,12 +371,6 @@ class WebRtcVoiceCodecs final {
           // Reset G722 sample rate to 16000 to match WebRTC.
           MaybeFixupG722(&voe_codec, 16000);
 
-          // Apply codec-specific settings.
-          if (IsCodec(codec, kIsacCodecName)) {
-            // If ISAC and an explicit bitrate is not specified,

[ossu, 2017/01/19 16:48:48]

After removing the rate setting code here and in webrtcsdp.cc, I ran through
*_tests and *_unittests with a CHECK here, that ensured voe_codec.rate was never
zero. It didn't trigger.
I expect zero is not a usable value for ISAC, since we previously had to change
it to -1. (This is, in it self, a bit strange).

[kwiberg-webrtc, 2017/01/23 15:18:11]

So in other words, in.bitrate was always -1 or >=1 here, causing the deleted
code to have no effect?

[ossu, 2017/01/23 15:33:18]

Yes, the block in webrtcsdp.cc ensured that we didn't set bitrate to -1. It set
in.bitrate to match the values that voe_codec.rate would already have been set
to by line 368, above.

[kwiberg-webrtc, 2017/01/23 15:38:40]

Acknowledged.

-            // enable auto bitrate adjustment.
-            voe_codec.rate = (in.bitrate > 0) ? in.bitrate : -1;
-          }
           *out = voe_codec;
         }
         return true;