Migrated audio_codec_speed_tests target to GN.

Review-Url: https://codereview.webrtc.org/2177373004
Cr-Commit-Position: refs/heads/master@{#13549}

webrtc/modules/audio_coding/BUILD.gn

@@ -1057,6 +1057,37 @@ if (rtc_include_tests) {
     }
   }
 
+  test("audio_codec_speed_tests") {
+    testonly = true
+    defines = []
+    deps = []
+    sources = [
+      "codecs/isac/fix/test/isac_speed_test.cc",
+      "codecs/opus/opus_speed_test.cc",
+      "codecs/tools/audio_codec_speed_test.cc",
+      "codecs/tools/audio_codec_speed_test.h",
+    ]
+
+    if (is_clang) {
+      # Suppress warnings from the Chromium Clang plugins
+      # (bugs.webrtc.org/163).
+      configs -= [ "//build/config/clang:find_bad_constructs" ]
+    }
+
+    if (is_android) {
+      deps += [ "//testing/android/native_test:native_test_native_code" ]
+    }
+
+    deps += [
+      ":isac_fix",
+      ":webrtc_opus",
+      "../../system_wrappers:system_wrappers_default",
+      "../../test:test_support_main",
+      "../audio_processing/",
+      "//testing/gtest",
+    ]
+  }
+
   source_set("neteq_test_support") {
     testonly = true
     sources = [