Stop running pub get at gclient sync time and fix build bugs

mojo/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("//build/module_args/mojo.gni")
 import("//mojo/public/mojo.gni")
 
 group("mojo") {
   # Meta-target, don't link into production code.
   testonly = true
   declare_args() {
     mojo_use_go = false
 
     # TODO(ncbray): support ASAN once NaCl's GN build is unforked.
     mojo_use_nacl = is_linux && !is_asan
   }
   deps = [
     ":tests",
     "//mojo/common",
     "//mojo/dart",
     "//mojo/public",
     "//mojo/services",
+    "//third_party/dart-pkg",
   ]
 
   if (is_android) {
     deps += [
       "//mojo/android",
       "//mojo/java",
       "//mojo/tools/android_shortcuts",
       "//mojo/tools:remote_file_reader",
     ]
   }
@@ skipping 33 matching lines @@
   # TODO(jamesr): We only support building V8 snapshot data on a linux host since it
   # needs a 32 bit toolchain and we don't have one configured for mac hosts.
   if (host_os == "linux") {
     deps += [ "//mojo/edk/js:tests" ]
   }
 
   if (mojo_use_prebuilt_network_service) {
     deps += [ "//mojo/public/tools:copy_network_service_apptests" ]
   }
 }