Add skeleton for select-to-speak component extension.

chrome/browser/resources/chromeos/select_to_speak/BUILD.gn

+# 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/features.gni")
+import("//testing/test.gni")
+import("//chrome/test/base/js2gtest.gni")
+import("//chrome/browser/resources/chromeos/chromevox/run_jsbundler.gni")
+
+assert(is_chromeos)
+
+select_to_speak_out_dir = "$root_out_dir/resources/chromeos/select_to_speak"
+
+group("select_to_speak") {
+  deps = [
+    ":select_to_speak_copied_files",
+    ":select_to_speak_guest_manifest",
+    ":select_to_speak_manifest",
+  ]
+}
+
+# Instead of setting up one copy target for each subdirectory, use a script
+# to copy all files.
+run_jsbundler("select_to_speak_copied_files") {
+  mode = "copy"
+  dest_dir = select_to_speak_out_dir
+  sources = [
+    "background.js",
+  ]
+  rewrite_rules = [
+    rebase_path(".", root_build_dir) + ":",
+    rebase_path(closure_library_dir, root_build_dir) + ":closure",
+  ]
+}
+
+# TODO: refactor this into another file like generate_manifest.gni
+# to share with other extensions.
+template("manifest") {
+  version_file = "//chrome/VERSION"
+  version_script = "//build/util/version.py"
+  template_file = "manifest.json.jinja2"
+  output_file = invoker.output_file
+  key = "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAukZ6JJWr0jHmFTkn0pcigpjI+cP0FqTo8FRIcCwy2fPeM+Ymf+7C9MK642i+Nhdr2qSsRF26AMIKbBdSDUnh04bfg5J/rKa/VO88LvXENYQMGhTo1y9mVg2OsbQJtEL9aTLU2G0SoKcr3g/+lggBKR5ydW1Qa0WGGAM9XrLm8iu/wn2uF4mfcMii6KfyEsAwWalpr/Td5WbtIoNNDpNeKO4ZSZJis1n9PZXqaOKpW7PqFDpEHw2PnPATxkcqj/wIx+Shgada0fhrzMlhXLhhj7ThSSWbuTz5n5NebuQ49/Z2ATgpBCSzYBVXEXMDe6LBBtGiZ/QR9UkA8Lz8bP6xIQIDAQAB"
+  action(target_name) {
+    script = "//chrome/browser/resources/chromeos/chromevox/tools/generate_manifest.py"
+    inputs = [
+      version_file,
+      version_script,
+    ]
+    sources = [
+      template_file,
+    ]
+    outputs = [
+      output_file,
+    ]
+    args = [
+      "--key=$key",
+      "--version_file=" + rebase_path(version_file, root_build_dir),
+      "--output_manifest=" + rebase_path(output_file, root_build_dir),
+    ]
+    if (defined(invoker.is_guest_manifest) && invoker.is_guest_manifest) {
+      args += [ "--is_guest_manifest=1" ]
+    }
+    args += rebase_path(sources, root_build_dir)
+  }
+}
+
+manifest("select_to_speak_manifest") {
+  output_file = "$select_to_speak_out_dir/manifest.json"
+}
+
+manifest("select_to_speak_guest_manifest") {
+  output_file = "$select_to_speak_out_dir/manifest_guest.json"
+  is_guest_manifest = true
+}