[iOS Policy] Improve policy mocking infra for unit tests

In preparation for CBCM reporting unit tests, this extends the mock
infrastructure for policy objects that will be involved. In particular:

- A new mock BrowserStatePolicyConnector was added
- The TestChromeBrowserState builder now supports building the browser
  state with a mock BrowserStatePolicyConnector
- The TestChromeBrowserStateManager can return a TestChromeBrowserState
  by path
- The TestingApplicationContext now creates a real
  BrowserPolicyConnector if its accessor is called

These are all needed for the ProfileReportGeneratorIOS unit tests, which
will come in a separate CL.

Bug: 1055318
Change-Id: I3428e56d695c014d63245be6493d527787343cce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2495265Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Guillaume Jenkins <gujen@google.com>
Cr-Commit-Position: refs/heads/master@{#820786}

ios/chrome/browser/browser_state/BUILD.gn

@@ -202,6 +202,7 @@ source_set("test_support") {
     "//ios/chrome/browser/bookmarks",
     "//ios/chrome/browser/history",
     "//ios/chrome/browser/net",
+    "//ios/chrome/browser/policy:policy",
     "//ios/chrome/browser/prefs",
     "//ios/chrome/browser/prefs:browser_prefs",
     "//ios/chrome/browser/sync/glue",

ios/chrome/browser/browser_state/test_chrome_browser_state.h

@@ -16,6 +16,7 @@
 #include "components/keyed_service/ios/refcounted_browser_state_keyed_service_factory.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/net/net_types.h"
+#include "ios/chrome/browser/policy/browser_state_policy_connector.h"
 
 namespace sync_preferences {
 class PrefServiceSyncable;
@@ -106,6 +107,9 @@ class TestChromeBrowserState : public ChromeBrowserState {
     void SetPrefService(
         std::unique_ptr<sync_preferences::PrefServiceSyncable> prefs);
 
+    void SetPolicyConnector(
+        std::unique_ptr<BrowserStatePolicyConnector> policy_connector);
+
     // Creates the TestChromeBrowserState using previously-set settings.
     std::unique_ptr<TestChromeBrowserState> Build();
 
@@ -117,6 +121,8 @@ class TestChromeBrowserState : public ChromeBrowserState {
     base::FilePath state_path_;
     std::unique_ptr<sync_preferences::PrefServiceSyncable> pref_service_;
 
+    std::unique_ptr<BrowserStatePolicyConnector> policy_connector_;
+
     TestingFactories testing_factories_;
     RefcountedTestingFactories refcounted_testing_factories_;
 
@@ -129,7 +135,8 @@ class TestChromeBrowserState : public ChromeBrowserState {
       const base::FilePath& path,
       std::unique_ptr<sync_preferences::PrefServiceSyncable> prefs,
       TestingFactories testing_factories,
-      RefcountedTestingFactories refcounted_testing_factories);
+      RefcountedTestingFactories refcounted_testing_factories,
+      std::unique_ptr<BrowserStatePolicyConnector> policy_connector);
 
  private:
   friend class Builder;
@@ -151,6 +158,8 @@ class TestChromeBrowserState : public ChromeBrowserState {
   std::unique_ptr<sync_preferences::PrefServiceSyncable> prefs_;
   sync_preferences::TestingPrefServiceSyncable* testing_prefs_;
 
+  std::unique_ptr<BrowserStatePolicyConnector> policy_connector_;
+
   // The incognito ChromeBrowserState instance that is associated with this
   // non-incognito ChromeBrowserState instance.
   std::unique_ptr<TestChromeBrowserState> otr_browser_state_;

ios/chrome/browser/browser_state/test_chrome_browser_state.mm

@@ -105,12 +105,14 @@ TestChromeBrowserState::TestChromeBrowserState(
     const base::FilePath& path,
     std::unique_ptr<sync_preferences::PrefServiceSyncable> prefs,
     TestingFactories testing_factories,
-    RefcountedTestingFactories refcounted_testing_factories)
+    RefcountedTestingFactories refcounted_testing_factories,
+    std::unique_ptr<BrowserStatePolicyConnector> policy_connector)
     : ChromeBrowserState(base::ThreadPool::CreateSequencedTaskRunner(
           {base::MayBlock(), base::TaskShutdownBehavior::BLOCK_SHUTDOWN})),
       state_path_(path),
       prefs_(std::move(prefs)),
       testing_prefs_(nullptr),
+      policy_connector_(std::move(policy_connector)),
       otr_browser_state_(nullptr),
       original_browser_state_(nullptr) {
   for (const auto& pair : testing_factories) {
@@ -236,9 +238,7 @@ PrefProxyConfigTracker* TestChromeBrowserState::GetProxyConfigTracker() {
 }
 
 BrowserStatePolicyConnector* TestChromeBrowserState::GetPolicyConnector() {
-  // TODO(crbug.com/1055318): Determine what level of support is needed for
-  // unittesting and return a mock or fake here.
-  return nullptr;
+  return policy_connector_.get();
 }
 
 PrefService* TestChromeBrowserState::GetPrefs() {
@@ -354,11 +354,17 @@ void TestChromeBrowserState::Builder::SetPrefService(
   pref_service_ = std::move(prefs);
 }
 
+void TestChromeBrowserState::Builder::SetPolicyConnector(
+    std::unique_ptr<BrowserStatePolicyConnector> policy_connector) {
+  DCHECK(!build_called_);
+  policy_connector_ = std::move(policy_connector);
+}
+
 std::unique_ptr<TestChromeBrowserState>
 TestChromeBrowserState::Builder::Build() {
   DCHECK(!build_called_);
   build_called_ = true;
   return base::WrapUnique(new TestChromeBrowserState(
       state_path_, std::move(pref_service_), std::move(testing_factories_),
-      std::move(refcounted_testing_factories_)));
+      std::move(refcounted_testing_factories_), std::move(policy_connector_)));
 }

ios/chrome/browser/browser_state/test_chrome_browser_state_manager.cc

@@ -30,6 +30,8 @@ ChromeBrowserState* TestChromeBrowserStateManager::GetLastUsedBrowserState() {
 
 ChromeBrowserState* TestChromeBrowserStateManager::GetBrowserState(
     const base::FilePath& path) {
+  if (browser_state_ && browser_state_->GetStatePath() == path)
+    return browser_state_.get();
   return nullptr;
 }
 

ios/chrome/browser/policy/BUILD.gn

@@ -87,6 +87,8 @@ source_set("feature_flags") {
 source_set("test_support") {
   testonly = true
   sources = [
+    "browser_state_policy_connector_mock.h",
+    "browser_state_policy_connector_mock.mm",
     "enterprise_policy_test_helper.cc",
     "enterprise_policy_test_helper.h",
     "test_platform_policy_provider.cc",

ios/chrome/browser/policy/browser_state_policy_connector.h

@@ -43,6 +43,8 @@ class BrowserStatePolicyConnector {
   policy::SchemaRegistry* GetSchemaRegistry() const { return schema_registry_; }
 
  private:
+  friend class BrowserStatePolicyConnectorMock;
+
   // |policy_providers_| contains a list of the policy providers available for
   // the PolicyService of this connector, in decreasing order of priority.
   //

ios/chrome/browser/policy/browser_state_policy_connector_mock.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 IOS_CHROME_BROWSER_POLICY_BROWSER_STATE_POLICY_CONNECTOR_MOCK_H_
+#define IOS_CHROME_BROWSER_POLICY_BROWSER_STATE_POLICY_CONNECTOR_MOCK_H_
+
+#include <memory>
+
+#include "ios/chrome/browser/policy/browser_state_policy_connector.h"
+
+namespace policy {
+class PolicyService;
+class SchemaRegistry;
+}  // namespace policy
+
+// BrowserStatePolicyConnector creates and manages the per-BrowserState policy
+// components and their integration with PrefService.
+class BrowserStatePolicyConnectorMock : public BrowserStatePolicyConnector {
+ public:
+  BrowserStatePolicyConnectorMock(
+      std::unique_ptr<policy::PolicyService> policy_service,
+      policy::SchemaRegistry* schema_registry);
+  ~BrowserStatePolicyConnectorMock();
+  BrowserStatePolicyConnectorMock(const BrowserStatePolicyConnectorMock&) =
+      delete;
+  BrowserStatePolicyConnectorMock& operator=(
+      const BrowserStatePolicyConnectorMock&) = delete;
+};
+
+#endif  // IOS_CHROME_BROWSER_POLICY_BROWSER_STATE_POLICY_CONNECTOR_MOCK_H_

ios/chrome/browser/policy/browser_state_policy_connector_mock.mm

+// 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.
+
+#import "ios/chrome/browser/policy/browser_state_policy_connector_mock.h"
+
+#include "components/policy/core/common/policy_service_impl.h"
+#include "components/policy/core/common/schema_registry.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+BrowserStatePolicyConnectorMock::BrowserStatePolicyConnectorMock(
+    std::unique_ptr<policy::PolicyService> policy_service,
+    policy::SchemaRegistry* schema_registry) {
+  policy_service_ = std::move(policy_service);
+  schema_registry_ = schema_registry;
+}
+
+BrowserStatePolicyConnectorMock::~BrowserStatePolicyConnectorMock() = default;

ios/chrome/test/BUILD.gn

@@ -54,6 +54,7 @@ source_set("test_support") {
     "//ios/chrome/browser/browser_state",
     "//ios/chrome/browser/browser_state:browser_state_impl",
     "//ios/chrome/browser/content_settings",
+    "//ios/chrome/browser/policy:policy",
     "//ios/chrome/browser/prefs:browser_prefs",
     "//ios/chrome/browser/safe_browsing:test_support",
     "//ios/chrome/browser/ui/util:multiwindow_util",

ios/chrome/test/testing_application_context.h

@@ -70,6 +70,8 @@ class TestingApplicationContext : public ApplicationContext {
   base::ThreadChecker thread_checker_;
   std::string application_locale_;
   PrefService* local_state_;
+  // Must be destroyed after |local_state_|.
+  std::unique_ptr<BrowserPolicyConnectorIOS> browser_policy_connector_;
   ios::ChromeBrowserStateManager* chrome_browser_state_manager_;
   std::unique_ptr<network_time::NetworkTimeTracker> network_time_tracker_;
   bool was_last_shutdown_clean_;

ios/chrome/test/testing_application_context.mm

@@ -12,6 +12,8 @@
 #include "base/time/default_tick_clock.h"
 #include "components/network_time/network_time_tracker.h"
 #include "components/safe_browsing/core/features.h"
+#include "ios/chrome/browser/policy/browser_policy_connector_ios.h"
+#include "ios/chrome/browser/policy/configuration_policy_handler_list_factory.h"
 #import "ios/chrome/browser/safe_browsing/fake_safe_browsing_service.h"
 #import "ios/public/provider/chrome/browser/chrome_browser_provider.h"
 #include "net/url_request/url_request_context_getter.h"
@@ -209,9 +211,12 @@ BrowserPolicyConnectorIOS*
 TestingApplicationContext::GetBrowserPolicyConnector() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
-  // TODO(crbug.com/1055318): Determine what level of support is needed for
-  // unittesting and return a mock or fake here.
-  return nullptr;
+  if (!browser_policy_connector_.get()) {
+    browser_policy_connector_ = std::make_unique<BrowserPolicyConnectorIOS>(
+        base::Bind(&BuildPolicyHandlerList, true));
+  }
+
+  return browser_policy_connector_.get();
 }
 
 BreadcrumbPersistentStorageManager*