Get mojo_shell building inside chromium checkout.

mojo/common/BUILD.gn

 # Copyright 2014 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")
 
 group("common") {
   deps = [
     ":common_base",
     ":url_type_converters",
   ]
 }
 
 # GYP version: mojo/mojo_base.gyp:mojo_common_lib
 component("common_base") {
   output_name = "mojo_common_lib"
 
   sources = [
     "common_type_converters.cc",
     "common_type_converters.h",
+    "data_pipe_file_utils.cc",
     "data_pipe_utils.cc",
     "data_pipe_utils.h",
     "handle_watcher.cc",
     "handle_watcher.h",
     "message_pump_mojo.cc",
     "message_pump_mojo.h",
     "message_pump_mojo_handler.h",
     "time_helper.cc",
     "time_helper.h",
+    "weak_binding_set.h",
+    "weak_interface_ptr_set.h",
   ]
 
   defines = [ "MOJO_COMMON_IMPLEMENTATION" ]
 
   deps = [
     "//base",
     "//base/third_party/dynamic_annotations",
     "//third_party/mojo/src/mojo/public/c/system:for_component",
   ]
 }
@@ skipping 29 matching lines @@
     "//third_party/mojo/src/mojo/public/cpp/test_support:test_utils",
     "//url",
   ]
 
   sources = [
     "common_type_converters_unittest.cc",
     "handle_watcher_unittest.cc",
     "message_pump_mojo_unittest.cc",
   ]
 }
+
+if (!is_component_build) {
+  source_set("tracing_impl") {
+    sources = [
+      "trace_controller_impl.cc",
+      "trace_controller_impl.h",
+      "tracing_impl.cc",
+      "tracing_impl.h",
+    ]
+
+    deps = [
+      "//base",
+      "//third_party/mojo/src/mojo/public/cpp/application",
+      "//third_party/mojo/src/mojo/public/cpp/bindings",
+      "//mojo/services/tracing:bindings",
+    ]
+  }
+}