GN: Change rtc_source_set targets --> rtc_static_library

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 2387c2e85b375f819b50960969716978c14a1240..54c33e346c87f0e1f6160ea4e38599cad44a5b14 100644
--- a/webrtc/modules/audio_processing/BUILD.gn
+++ b/webrtc/modules/audio_processing/BUILD.gn
@@ -17,7 +17,7 @@ declare_args() {
   aec_untrusted_delay_for_testing = false
 }
 
-rtc_source_set("audio_processing") {
+rtc_static_library("audio_processing") {
   sources = [
     "aec/aec_core.cc",
     "aec/aec_core.h",
@@ -253,7 +253,7 @@ if (rtc_enable_protobuf) {
 }
 
 if (current_cpu == "x86" || current_cpu == "x64") {
-  rtc_source_set("audio_processing_sse2") {
+  rtc_static_library("audio_processing_sse2") {
     sources = [
       "aec/aec_core_sse2.cc",
       "aec/aec_rdft_sse2.cc",
@@ -272,7 +272,7 @@ if (current_cpu == "x86" || current_cpu == "x64") {
 }
 
 if (rtc_build_with_neon) {
-  rtc_source_set("audio_processing_neon") {
+  rtc_static_library("audio_processing_neon") {
     sources = [
       "aec/aec_core_neon.cc",
       "aec/aec_rdft_neon.cc",
@@ -453,7 +453,7 @@ if (rtc_include_tests) {
       proto_out_dir = "webrtc/modules/audio_processing"
     }
 
-    rtc_source_set("audioproc_protobuf_utils") {
+    rtc_static_library("audioproc_protobuf_utils") {
       sources = [
         "test/protobuf_utils.cc",
         "test/protobuf_utils.h",