Split apart the PPAPI GN targets

ppapi/examples/audio/BUILD.gn

Index: ppapi/examples/audio/BUILD.gn
diff --git a/chrome/browser/metro_utils/BUILD.gn b/ppapi/examples/audio/BUILD.gn
similarity index 57%
copy from chrome/browser/metro_utils/BUILD.gn
copy to ppapi/examples/audio/BUILD.gn
index 86a28875cc8bb6787a0807467adcbb3072e01ce0..f1243d68bbba082d4b7194729ad0d2cc5993220f 100644
--- a/chrome/browser/metro_utils/BUILD.gn
+++ b/ppapi/examples/audio/BUILD.gn
@@ -1,14 +1,15 @@
 # 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.
+# found in the LICENSE file.
 
-source_set("metro_utils") {
-  deps = [
-    "//base",
-    "//chrome/installer/util",
-  ]
+import("//ppapi/examples/ppapi_example.gni")
+
+ppapi_example("audio") {
+  output_name = "ppapi_example_audio"
   sources = [
-    "metro_chrome_win.cc",
-    "metro_chrome_win.h",
+    "audio.cc",
+  ]
+  deps = [
+    "//ppapi/cpp",
   ]
 }