Add a general PostProcessorUnittest.

chromecast/media/cma/backend/alsa/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/chromecast_build.gni")
 import("//chromecast/chromecast.gni")
 import("//media/media_options.gni")
 import("//testing/test.gni")
 
@@ skipping 142 matching lines @@
     ":governor",
   ]
 }
 
 test("libcast_governor_unittests") {
   sources = [
     "post_processors/governor_unittest.cc",
   ]
   deps = [
     ":governor",
+    ":post_processor_test_support",
     "//base",
     "//base/test:run_all_unittests",
     "//media",
     "//testing/gtest",
   ]
 }
 
 source_set("governor") {
   sources = [
     "post_processors/governor.cc",
     "post_processors/governor.h",
   ]
   deps = [
     ":slew_volume",
     "//base",
     "//chromecast/base",
     "//chromecast/public/media",
   ]
   public_configs = [ "//chromecast/public:public_config" ]
 }
+
+source_set("post_processor_test_support") {
+  testonly = true
+  sources = [
+    "post_processors/post_processor_unittest.cc",
+    "post_processors/post_processor_unittest.h",
+  ]
+  deps = [
+    "//base",
+    "//chromecast/public/media",
+    "//testing/gtest",
+  ]
+}