[s13n] Convert UserPolicySigninServiceTest way from SigninManager

This makes use of the helper IdentityTestEnvironmentProfileAdaptor.
In order to be able to construct the Profile object the same way as the
test originally was, and additional optional parameter was added to
IdentityTestEnvironmentProfileAdaptor::CreateProfileForIdentityTestEnvironment.

BUG=890783

Change-Id: I5c2a48dd4aa7e7377f8a7806717b513b7f27bfe0
Reviewed-on: https://chromium-review.googlesource.com/c/1301814Reviewed-by: Colin Blundell <blundell@chromium.org>
Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Commit-Queue: Antonio Gomes <tonikitoo@igalia.com>
Cr-Commit-Position: refs/heads/master@{#606434}

chrome/browser/signin/identity_test_environment_profile_adaptor.cc

@@ -36,7 +36,8 @@ std::unique_ptr<TestingProfile> IdentityTestEnvironmentProfileAdaptor::
 // static
 std::unique_ptr<TestingProfile>
 IdentityTestEnvironmentProfileAdaptor::CreateProfileForIdentityTestEnvironment(
-    const TestingProfile::TestingFactories& input_factories) {
+    const TestingProfile::TestingFactories& input_factories,
+    std::unique_ptr<sync_preferences::PrefServiceSyncable> prefs) {
   TestingProfile::Builder builder;
 
   for (auto& input_factory : input_factories) {
@@ -47,6 +48,9 @@ IdentityTestEnvironmentProfileAdaptor::CreateProfileForIdentityTestEnvironment(
     builder.AddTestingFactory(identity_factory.first, identity_factory.second);
   }
 
+  if (prefs)
+    builder.SetPrefService(std::move(prefs));
+
   return builder.Build();
 }
 

chrome/browser/signin/identity_test_environment_profile_adaptor.h

@@ -6,6 +6,7 @@
 #define CHROME_BROWSER_SIGNIN_IDENTITY_TEST_ENVIRONMENT_PROFILE_ADAPTOR_H_
 
 #include "chrome/test/base/testing_profile.h"
+#include "components/sync_preferences/testing_pref_service_syncable.h"
 #include "services/identity/public/cpp/identity_test_environment.h"
 
 // Adaptor that supports identity::IdentityTestEnvironment's usage in testing
@@ -24,10 +25,11 @@ class IdentityTestEnvironmentProfileAdaptor {
   CreateProfileForIdentityTestEnvironment();
 
   // Like the above, but additionally configures the returned Profile with
-  // |input_factories|.
+  // |input_factories| and |prefs|.
   static std::unique_ptr<TestingProfile>
   CreateProfileForIdentityTestEnvironment(
-      const TestingProfile::TestingFactories& input_factories);
+      const TestingProfile::TestingFactories& input_factories,
+      std::unique_ptr<sync_preferences::PrefServiceSyncable> prefs = nullptr);
 
   // Appends the set of testing factories that identity::IdentityTestEnvironment
   // requires to |factories_to_append_to|, which should be the set of testing