Readd the clipboard service and get it compiling again.

components/mus/clipboard/BUILD.gn

Index: components/mus/clipboard/BUILD.gn
diff --git a/components/mus/clipboard/BUILD.gn b/components/mus/clipboard/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..af5cdd43db1cd7be64723c13c39c3d18b6550a80
--- /dev/null
+++ b/components/mus/clipboard/BUILD.gn
@@ -0,0 +1,57 @@
+# 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("//mojo/public/mojo_application.gni")
+import("//mojo/public/mojo_application_manifest.gni")
+import("//testing/test.gni")
+
+source_set("lib") {
+  sources = [
+    "clipboard_impl.cc",
+    "clipboard_impl.h",
+  ]
+
+  deps = [
+    "//base",
+    "//components/mus/public/interfaces",
+    "//mojo/public/cpp/bindings",
+    "//mojo/public/cpp/bindings:callback",
+    "//services/shell/public/cpp",
+    "//services/tracing/public/cpp",
+  ]
+}
+
+group("tests") {
+  testonly = true
+  deps = [
+    ":mus_clipboard_unittests",
+  ]
+}
+
+test("mus_clipboard_unittests") {
+  sources = [
+    "clipboard_unittest.cc",
+  ]
+
+  deps = [
+    "//base",
+    "//components/mus/public/interfaces",
+    "//mojo/common",
+    "//services/shell/public/cpp:shell_test_support",
+    "//services/shell/public/cpp:sources",
+    "//services/shell/public/cpp/test:run_all_shelltests",
+  ]
+
+  data_deps = [
+    ":test_manifest",
+    ":lib",
+    "//components/mus:mus",
+  ]
+}
+
+mojo_application_manifest("test_manifest") {
+  type = "exe"
+  application_name = "mus_clipboard_unittests"
+  source = "test_manifest.json"
+}