Add support for ProxyResolverErrorObserver to ProxyResolverMojo.

net/BUILD.gn

 # Copyright (c) 2013 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/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/module_args/v8.gni")
 import("//url/config.gni")
 import("//testing/test.gni")
@@ skipping 821 matching lines @@
   source_set("net_utility_services") {
     sources = [
       "dns/host_resolver_mojo.cc",
       "dns/host_resolver_mojo.h",
       "proxy/load_state_change_coalescer.cc",
       "proxy/load_state_change_coalescer.h",
       "proxy/mojo_proxy_resolver_factory_impl.cc",
       "proxy/mojo_proxy_resolver_factory_impl.h",
       "proxy/mojo_proxy_resolver_impl.cc",
       "proxy/mojo_proxy_resolver_impl.h",
+      "proxy/proxy_resolver_error_observer_mojo.cc",
+      "proxy/proxy_resolver_error_observer_mojo.h",
     ]
 
     deps = [
       ":net_with_v8",
     ]
 
     public_deps = [
       ":mojo_type_converters",
       ":net",
       "//mojo/common",
@@ skipping 634 matching lines @@
         "//mojo/environment:chromium",
         "//third_party/mojo/src/mojo/edk/system",
       ]
     } else {
       sources -= [
         "dns/host_resolver_mojo_unittest.cc",
         "dns/mojo_host_resolver_impl_unittest.cc",
         "proxy/load_state_change_coalescer_unittest.cc",
         "proxy/mojo_proxy_resolver_factory_impl_unittest.cc",
         "proxy/mojo_proxy_resolver_impl_unittest.cc",
+        "proxy/proxy_resolver_error_observer_mojo_unittest.cc",
         "proxy/proxy_resolver_mojo_unittest.cc",
         "proxy/proxy_service_mojo_unittest.cc",
       ]
     }
 
     if (!enable_mdns) {
       sources -= [
         "dns/mdns_cache_unittest.cc",
         "dns/mdns_client_unittest.cc",
         "dns/record_parsed_unittest.cc",
@@ skipping 109 matching lines @@
   } else {
     sources -= [ "proxy/proxy_resolver_perftest.cc" ]
   }
 
   if (is_win && icu_use_data_file) {
     # This is needed to trigger the dll copy step on windows.
     # TODO(mark): Specifying this here shouldn't be necessary.
     deps += [ "//third_party/icu:icudata" ]
   }
 }