Moved the functionality in aec_core_internal.h into other
files.

The purpose of this CL is to simplify upcoming AEC algorithm
changes.

The changes should be bitexact.

The presubmit was bypassed due to a presubmit complaint
about usage of short instead of int16_t which will be
addressed in upcoming CLs.

BUG=webrtc:5298, webrtc:5201

NOPRESUBMIT=true

Review-Url: https://codereview.webrtc.org/1949803004
Cr-Commit-Position: refs/heads/master@{#12662}
diff --git a/webrtc/modules/audio_processing/audio_processing.gypi b/webrtc/modules/audio_processing/audio_processing.gypi
index 225dffd..e6eab36 100644
--- a/webrtc/modules/audio_processing/audio_processing.gypi
+++ b/webrtc/modules/audio_processing/audio_processing.gypi
@@ -35,7 +35,7 @@
       'sources': [
         'aec/aec_core.cc',
         'aec/aec_core.h',
-        'aec/aec_core_internal.h',
+        'aec/aec_core_optimized_methods.h',
         'aec/aec_rdft.cc',
         'aec/aec_rdft.h',
         'aec/aec_resampler.cc',