Moves helpers for PolicyPrefsTest into a shared helper file.

These helpers are moved into //components/policy/core/common so that
they can be used on iOS as well.

BUG=1069528

Change-Id: I66adcf426e81ff5bdc430146e802745d276fd814
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2144266
Commit-Queue: Rohit Rao <rohitrao@chromium.org>
Reviewed-by: Owen Min <zmin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#759285}

components/policy/core/browser/BUILD.gn

@@ -91,6 +91,13 @@ jumbo_static_library("test_support") {
     "configuration_policy_pref_store_test.h",
   ]
 
+  if (!is_android && !is_fuchsia) {
+    sources += [
+      "policy_pref_mapping_test.cc",
+      "policy_pref_mapping_test.h",
+    ]
+  }
+
   public_deps = [
     ":browser",
     "//base",
@@ -101,7 +108,12 @@ jumbo_static_library("test_support") {
     "//components/policy:generated",
     "//components/policy/core/common:test_support",
   ]
-  deps = [ "//testing/gtest" ]
+  deps = [
+    "//build:branding_buildflags",
+    "//components/prefs",
+    "//testing/gtest",
+    "//url",
+  ]
 }
 
 source_set("unit_tests") {

components/policy/core/browser/policy_pref_mapping_test.h

+// Copyright 2020 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.
+
+#ifndef COMPONENTS_POLICY_CORE_BROWSER_POLICY_PREF_MAPPING_TEST_H_
+#define COMPONENTS_POLICY_CORE_BROWSER_POLICY_PREF_MAPPING_TEST_H_
+
+#include <string>
+
+namespace base {
+class FilePath;
+}
+
+namespace policy {
+class MockConfigurationPolicyProvider;
+}
+
+class PrefService;
+
+namespace policy {
+
+// Verifies that all of the policies have a test case listed in the JSON file at
+// |test_case_path|.
+void VerifyAllPoliciesHaveATestCase(const base::FilePath& test_case_path);
+
+// Verifies that policies make their corresponding preferences become managed,
+// and that the user can't override that setting.  Loads test cases from the
+// JSON file at |test_case_path| and updates policies using the given
+// |provider|.  Does not verify any prefs which start with
+// |skipped_pref_prefix|, if non-empty.
+void VerifyPolicyToPrefMappings(const base::FilePath& test_case_path,
+                                PrefService* local_state,
+                                PrefService* user_prefs,
+                                MockConfigurationPolicyProvider* provider,
+                                const std::string& skipped_pref_prefix);
+
+}  // namespace policy
+
+#endif  // COMPONENTS_POLICY_CORE_BROWSER_POLICY_PREF_MAPPING_TEST_H_