Reland of actor webrtc_perf_tests into several source_sets. (patchset #1 id:1 of https://codereview.webrtc.org/2613913002/ )

Reason for revert:
Try again.

Original issue's description:
> Revert of Refactor webrtc_perf_tests into several source_sets. (patchset #5 id:100001 of https://codereview.webrtc.org/2609403002/ )
>
> Reason for revert:
> Probably cause unexpected performance regression
> BUG=chromium:678569
>
> Original issue's description:
> > Refactor webrtc_perf_tests into several source_sets.
> >
> > BUG=webrtc:6954
> >
> > Review-Url: https://codereview.webrtc.org/2609403002
> > Cr-Commit-Position: refs/heads/master@{#15902}
> > Committed: https://chromium.googlesource.com/external/webrtc/+/0b5a26a5768618e5d850aa7ea97cb348fe5302f7
>
> TBR=kjellander@webrtc.org,ehmaldonado@webrtc.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=webrtc:6954
>
> Review-Url: https://codereview.webrtc.org/2613913002
> Cr-Commit-Position: refs/heads/master@{#15916}
> Committed: https://chromium.googlesource.com/external/webrtc/+/5fbcd228f0781526ce2cbafba0a1f39f481ad81b

TBR=kjellander@webrtc.org,danilchap@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:678569

Review-Url: https://codereview.webrtc.org/2615873002
Cr-Commit-Position: refs/heads/master@{#15919}
diff --git a/webrtc/modules/audio_processing/BUILD.gn b/webrtc/modules/audio_processing/BUILD.gn
index 049a4e1..5cbd97d 100644
--- a/webrtc/modules/audio_processing/BUILD.gn
+++ b/webrtc/modules/audio_processing/BUILD.gn
@@ -411,6 +411,35 @@
     }
   }
 
+  rtc_source_set("audio_processing_perf_tests") {
+    # Has problems with autogenerated targets on Android and iOS
+    # Dependency chain (there may also be others):
+    #  //webrtc/modules/audio_processing:audio_processing_perf_tests -->
+    #  //webrtc/modules:modules_unittests --[private]-->
+    #  //webrtc/modules:modules_unittests_apk -->
+    #  //webrtc/modules:modules_unittests_apk__create -->
+    #  //webrtc/modules:modules_unittests_apk__create__finalize -->
+    #  //webrtc/modules:modules_unittests_apk__create__package --[private]-->
+    #  //webrtc/modules:_modules_unittests__library
+    check_includes = false
+    testonly = true
+    sources = [
+      "audio_processing_performance_unittest.cc",
+      "level_controller/level_controller_complexity_unittest.cc",
+      "residual_echo_detector_complexity_unittest.cc",
+    ]
+    deps = [
+      ":audio_processing",
+      ":audioproc_test_utils",
+      "//testing/gtest",
+    ]
+    if (rtc_enable_intelligibility_enhancer) {
+      defines = [ "WEBRTC_INTELLIGIBILITY_ENHANCER=1" ]
+    } else {
+      defines = [ "WEBRTC_INTELLIGIBILITY_ENHANCER=0" ]
+    }
+  }
+
   rtc_executable("unpack_aecdump") {
     testonly = true
     sources = [