[Watch flakes]: Fix flakes from NetworkService.

This CL cause NetworkService::CreateForTesting to
use a mock NetworkChangeNotifier which does not observe network changes

Bug: 1011275
Change-Id: I6de34b7a5f6c5af5128cfc000ed63481f3351325
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1864359
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Reviewed-by: Eric Orth <ericorth@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709257}

services/network/network_service.cc

@@ -329,8 +329,12 @@ std::unique_ptr<NetworkService> NetworkService::Create(
 }
 
 std::unique_ptr<NetworkService> NetworkService::CreateForTesting() {
-  return std::make_unique<NetworkService>(
-      std::make_unique<service_manager::BinderRegistry>());
+  auto network_service = std::make_unique<NetworkService>(
+      std::make_unique<service_manager::BinderRegistry>(), mojo::NullReceiver(),
+      true /* delay_initialization_until_set_client */);
+  network_service->Initialize(mojom::NetworkServiceParams::New(),
+                              true /* mock_network_change_notifier */);
+  return network_service;
 }
 
 void NetworkService::RegisterNetworkContext(NetworkContext* network_context) {

services/network/network_service.h

@@ -86,8 +86,9 @@ class COMPONENT_EXPORT(NETWORK_SERVICE) NetworkService
   static std::unique_ptr<NetworkService> Create(
       mojo::PendingReceiver<mojom::NetworkService> receiver);
 
-  // Creates a testing instance of NetworkService not bound to an actual
-  // Service pipe. This instance must be driven by direct calls onto the
+  // Creates a testing instance of NetworkService not bound to an actual Service
+  // pipe. This will cause NetworkChangeNotifier, unless already created, to be
+  // mocked. This instance must be driven by direct calls onto the
   // NetworkService object.
   static std::unique_ptr<NetworkService> CreateForTesting();