AGC2 as a new APM sub-module operating with hard-coded gain.

webrtc/modules/audio_processing/BUILD.gn

Index: webrtc/modules/audio_processing/BUILD.gn
diff --git a/webrtc/modules/audio_processing/BUILD.gn b/webrtc/modules/audio_processing/BUILD.gn
index ff9a4d6474c89005eaf4d139cc3c332f40b23037..7f7512c015a5a1a6ee08f4ad30459b2c78889a6d 100644
--- a/webrtc/modules/audio_processing/BUILD.gn
+++ b/webrtc/modules/audio_processing/BUILD.gn
@@ -108,6 +108,9 @@ rtc_static_library("audio_processing") {
     "agc/loudness_histogram.h",
     "agc/utility.cc",
     "agc/utility.h",
+    "agc2/agc2.h",
+    "agc2/agc2_impl.cc",
+    "agc2/agc2_impl.h",

[aleloi, 2017/05/02 10:11:53]

I wonder how difficult it would be to write new submodules as separate build
targets. Or maybe split the audio_processing target up as part of our work.
Putting the build files in a subdirectory would simplify this file.

[AleBzk, 2017/05/02 11:31:54]

Personally, I like your idea a lot. I'll do this change since we have everything
in agc2/.

[aleloi, 2017/05/18 15:01:17]

Did you decide to keep everythnig in ':audio_processing'?

[peah-webrtc, 2017/05/18 20:17:52]

I think the build target idea sounds great as well. But I'm also ok with keeping
everything in audio_processing.

[AleBzk, 2017/05/19 13:15:41]

Let's make another CL for this.

     "audio_buffer.cc",
     "audio_buffer.h",
     "audio_processing_impl.cc",
@@ -499,6 +502,8 @@ if (rtc_include_tests) {
       "agc/agc_manager_direct_unittest.cc",
       "agc/loudness_histogram_unittest.cc",
       "agc/mock_agc.h",
+      "agc2/agc2_mock.h",

[aleloi, 2017/05/02 10:11:53]

Same for tests. New module unittests could have a separate target, on which this
target depends.

[AleBzk, 2017/05/02 11:31:54]

Yup.

+      "agc2/agc2_unittest.cc",
       "audio_buffer_unittest.cc",
       "beamformer/array_util_unittest.cc",
       "beamformer/complex_matrix_unittest.cc",