Add an Android sample app for Telemetry tests.

tools/android/push_apps_to_background/BUILD.gn

Index: tools/android/push_apps_to_background/BUILD.gn
diff --git a/tools/android/push_apps_to_background/BUILD.gn b/tools/android/push_apps_to_background/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..cd90aa39b8e2b9ee5d8827b47393dcb96c28e814
--- /dev/null
+++ b/tools/android/push_apps_to_background/BUILD.gn
@@ -0,0 +1,23 @@
+# Copyright 2016 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/config/android/rules.gni")
+import("//testing/test.gni")
+
+# Mark all targets as test only.
+testonly = true
+
+android_apk("push_apps_to_background_apk") {
+  apk_name = "PushAppsToBackground"
+  java_files = [ "src/org/chromium/push_apps_to_background/PushAppsToBackgroundActivity.java" ]
+  android_manifest = "AndroidManifest.xml"
+  deps = [
+    ":push_apps_to_background_apk_resources",
+  ]
+}
+
+android_resources("push_apps_to_background_apk_resources") {
+  resource_dirs = [ "res" ]
+  custom_package = "org.chromium.push_apps_to_background"
+}