Moving FFT on farend signal to where it is used in AEC (bit exact).

webrtc/modules/audio_processing/aec/echo_cancellation.c

Index: webrtc/modules/audio_processing/aec/echo_cancellation.c
diff --git a/webrtc/modules/audio_processing/aec/echo_cancellation.c b/webrtc/modules/audio_processing/aec/echo_cancellation.c
index cf38c67b4d4e46962a238f063d36be4fe7f894e2..aab1718b242865fa32b17d2df9b3cc06f3e6db6f 100644
--- a/webrtc/modules/audio_processing/aec/echo_cancellation.c
+++ b/webrtc/modules/audio_processing/aec/echo_cancellation.c
@@ -317,7 +317,8 @@ int32_t WebRtcAec_BufferFarend(void* aecInst,
   // Write the time-domain data to |far_pre_buf|.
   WebRtc_WriteBuffer(aecpc->far_pre_buf, farend_ptr, newNrOfSamples);
 
-  // Transform to frequency domain if we have enough data.
+  // TODO(minyue): reduce to |PART_LEN| samples for each buffering, when
+  // WebRtcAec_BufferFarendPartition() is changed to take |PART_LEN| samples.
   while (WebRtc_available_read(aecpc->far_pre_buf) >= PART_LEN2) {
     // We have enough data to pass to the FFT, hence read PART_LEN2 samples.
     {
@@ -325,10 +326,6 @@ int32_t WebRtcAec_BufferFarend(void* aecInst,
       float tmp[PART_LEN2];
       WebRtc_ReadBuffer(aecpc->far_pre_buf, (void**)&ptmp, tmp, PART_LEN2);
       WebRtcAec_BufferFarendPartition(aecpc->aec, ptmp);
-#ifdef WEBRTC_AEC_DEBUG_DUMP
-      WebRtc_WriteBuffer(
-          WebRtcAec_far_time_buf(aecpc->aec), &ptmp[PART_LEN], 1);
-#endif
     }
 
     // Rewind |far_pre_buf| PART_LEN samples for overlap before continuing.