Skeleton for proto_zero_plugin.

components/tracing/proto_zero_plugin/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("//third_party/protobuf/proto_library.gni")
+
+if (current_toolchain == host_toolchain) {
+  executable("proto_zero_plugin") {
+    sources = [
+      "proto_zero_generator.cc",
+      "proto_zero_generator.h",
+      "proto_zero_plugin.cc",
+    ]
+    deps = [
+      "//third_party/protobuf:protoc_lib",
+    ]
+  }
+}
+
+# For unit tests.
+proto_library("mock_messages") {

[Primiano Tucci (use gerrit), 2016/07/13 16:52:31]

ditto about proto_zero_examples

+  visibility = [ "//components/tracing/*" ]
+
+  sources = [
+    "mock_messages.proto",
+  ]
+
+  plugin_label = ":proto_zero_plugin($host_toolchain)"
+  generator_plugin = rebase_path(
+          get_label_info(plugin_label, "root_out_dir") + "/proto_zero_plugin",

[Primiano Tucci (use gerrit), 2016/07/13 16:52:32]

uh, this is interestingly long. Did you take this from somewhere or came up
yourself with this?

+          root_build_dir)
+
+  proto_out_dir = "components/tracing/proto_zero_plugin"
+  generator_plugin_suffix = ".zeropb"
+  generate_cc = false
+  generate_python = false
+
+  deps = [
+    plugin_label,
+  ]
+}