Fix Gn Untracked headers in webrtc/common_audio

common_audio/BUILD.gn

Index: common_audio/BUILD.gn
diff --git a/common_audio/BUILD.gn b/common_audio/BUILD.gn
index 8cfd642d971c50d4915a00ea167e3ef114c7213d..afb5e92cf96ac861ace3e40da00db33a3ae2efa7 100644
--- a/common_audio/BUILD.gn
+++ b/common_audio/BUILD.gn
@@ -104,6 +104,18 @@ rtc_static_library("common_audio") {
   }
 }
 
+rtc_source_set("mock_common_audio") {
+  testonly = true
+  sources = [
+    "mocks/mock_smoothing_filter.h",
+    "vad/mock/mock_vad.h",
+  ]
+  deps = [
+    ":common_audio",
+    "../test:test_support",
+  ]
+}
+
 rtc_source_set("common_audio_c_arm_asm") {
   visibility = [ ":*" ]  # Only targets in this file can depend on this.
   sources = []
@@ -144,6 +156,7 @@ rtc_source_set("common_audio_c") {
     "signal_processing/include/real_fft.h",
     "signal_processing/include/signal_processing_library.h",
     "signal_processing/include/spl_inl.h",
+    "signal_processing/include/spl_inl_armv7.h",
     "signal_processing/levinson_durbin.c",
     "signal_processing/lpc_to_refl_coef.c",
     "signal_processing/min_max_operations.c",