Add a simple, safe gain PostProcessor.

chromecast/BUILD.gn

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/buildflag_header.gni")
 import("//build/config/features.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/ui.gni")
 import("//chromecast/build/tests/cast_test.gni")
 import("//chromecast/chromecast.gni")
@@ skipping 42 matching lines @@
     if (use_aura) {
       tests += [ "//chromecast/graphics:cast_graphics_unittests" ]
     }
   }
 
   if (is_linux) {
     tests += [ "//chromecast/crash:cast_crash_unittests" ]
   }
 
   if (!is_android && use_alsa) {
-    tests += [
-      "//chromecast/media/cma/backend/alsa:cast_alsa_cma_backend_unittests",
-      "//chromecast/media/cma/backend/alsa:libcast_governor_unittests",
-      "//chromecast/media/cma/backend/alsa:slew_volume_unittests",
-    ]
+    tests += [ "//chromecast/media/cma/backend/alsa:cast_alsa_cma_backend_unittests" ]
   }
 
   if (!is_android) {
     tests += [
       ":cast_shell_browsertests",
       ":cast_shell_unittests",
       "//ipc:ipc_tests",
       "//jingle:jingle_unittests",
       "//url:url_unittests",
     ]
@@ skipping 432 matching lines @@
     shared_libraries = [ "//chromecast/android:libcast_shell_android" ]
 
     deps = [
       ":cast_shell_apk_assets",
       "//base:base_java",
       "//chromecast/android:libcast_shell_android",
       "//chromecast/browser/android:cast_shell_java",
     ]
   }
 }