Blimp: create MessageDispatcher class.

blimp/common/net/BUILD.gn

+# 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.
+
+import("//testing/test.gni")
+
+static_library("net") {
+  sources = [
+    "message_dispatcher.cc",
+    "message_dispatcher.h",
+  ]
+  public_deps = [
+    "../proto",
+  ]
+}
+
+test("blimp_net_unit_tests") {
+  sources = [
+    "message_dispatcher_unittest.cc",
+  ]
+  deps = [
+    ":net",
+    "//base",
+    "//base/test:test_support",
+    "//base/test:run_all_unittests",
+    "//testing/gmock",
+  ]
+}