Fixed Aec handle index in EchoCancellationImpl that was not updated as it should.

webrtc/modules/audio_processing/echo_cancellation_impl.cc

Index: webrtc/modules/audio_processing/echo_cancellation_impl.cc
diff --git a/webrtc/modules/audio_processing/echo_cancellation_impl.cc b/webrtc/modules/audio_processing/echo_cancellation_impl.cc
index 1c3ebe4abb5901ba7b44bf329b6087adc249f864..1bac629c9e752f1597b75231e73cbacb2520b542 100644
--- a/webrtc/modules/audio_processing/echo_cancellation_impl.cc
+++ b/webrtc/modules/audio_processing/echo_cancellation_impl.cc
@@ -116,6 +116,8 @@ int EchoCancellationImpl::ProcessRenderAudio(const AudioBuffer* audio) {
                                   audio->split_bands_const_f(j)[kBand0To8kHz],
                                   (audio->split_bands_const_f(j)[kBand0To8kHz] +
                                    audio->num_frames_per_band()));
+
+      handle_index++;
     }
   }