[ios] Calls BrowserPolicyConnectorIOS::Init() once threads are started.

BUG=1024115

Change-Id: I01f1a5f11710a6956cd17ada97b462c250c64d84
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2079391
Commit-Queue: Rohit Rao <rohitrao@chromium.org>
Reviewed-by: Owen Min <zmin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#745265}

ios/chrome/browser/application_context_impl.cc

@@ -132,6 +132,20 @@ void ApplicationContextImpl::PreCreateThreads() {
 
 void ApplicationContextImpl::PreMainMessageLoopRun() {
   DCHECK(thread_checker_.CalledOnValidThread());
+
+  // BrowserPolicyConnectorIOS is created very early because local_state()
+  // needs policy to be initialized with the managed preference values.
+  // However, policy fetches from the network and loading of disk caches
+  // requires that threads are running; this Init() call lets the connector
+  // resume its initialization now that the loops are spinning and the
+  // system request context is available for the fetchers.
+  BrowserPolicyConnectorIOS* browser_policy_connector =
+      GetBrowserPolicyConnector();
+  if (browser_policy_connector) {
+    DCHECK(IsEnterprisePolicyEnabled());
+    browser_policy_connector->Init(GetLocalState(),
+                                   GetSharedURLLoaderFactory());
+  }
 }
 
 void ApplicationContextImpl::StartTearDown() {

ios/chrome/browser/policy/browser_policy_connector_ios.mm

@@ -48,7 +48,7 @@ ConfigurationPolicyProvider* BrowserPolicyConnectorIOS::GetPlatformProvider() {
 void BrowserPolicyConnectorIOS::Init(
     PrefService* local_state,
     scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory) {
-  InitInternal(local_state, nullptr);
+  InitInternal(local_state, /*device_management_service=*/nullptr);
 }
 
 bool BrowserPolicyConnectorIOS::IsEnterpriseManaged() const {

ios/chrome/browser/prefs/BUILD.gn

@@ -48,6 +48,8 @@ source_set("browser_prefs") {
     "//components/omnibox/browser",
     "//components/password_manager/core/browser",
     "//components/payments/core",
+    "//components/policy/core/browser",
+    "//components/policy/core/common",
     "//components/pref_registry",
     "//components/prefs",
     "//components/proxy_config",

ios/chrome/browser/prefs/browser_prefs.mm

@@ -28,6 +28,8 @@
 #include "components/omnibox/browser/zero_suggest_provider.h"
 #include "components/password_manager/core/browser/password_manager.h"
 #include "components/payments/core/payment_prefs.h"
+#include "components/policy/core/browser/browser_policy_connector.h"
+#include "components/policy/core/common/policy_statistics_collector.h"
 #include "components/pref_registry/pref_registry_syncable.h"
 #include "components/prefs/pref_service.h"
 #include "components/proxy_config/pref_proxy_config_tracker_impl.h"
@@ -94,6 +96,8 @@ void RegisterLocalStatePrefs(PrefRegistrySimple* registry) {
   IOSChromeMetricsServiceClient::RegisterPrefs(registry);
   network_time::NetworkTimeTracker::RegisterPrefs(registry);
   ios::NotificationPromo::RegisterPrefs(registry);
+  policy::BrowserPolicyConnector::RegisterPrefs(registry);
+  policy::PolicyStatisticsCollector::RegisterPrefs(registry);
   PrefProxyConfigTrackerImpl::RegisterPrefs(registry);
   rappor::RapporServiceImpl::RegisterPrefs(registry);
   sessions::SessionIdGenerator::RegisterPrefs(registry);