Add Desktop iOS promotion logging to chrome ios app.

ios/chrome/browser/desktop_promotion/desktop_promotion_prefs.mm

+// Copyright 2017 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.
+
+#include "ios/chrome/browser/desktop_promotion/desktop_promotion_prefs.h"
+
+#include "components/pref_registry/pref_registry_syncable.h"
+#include "components/prefs/pref_service.h"
+
+namespace prefs {
+
+// Which desktop ios promotion initiated sent the sms.
+const char kDesktopIOSPromotionSMSEntryPoint[] =
+    "ios.desktop_ios_promo_sms_entrypoint";
+
+// Which desktop ios promotions did the user see.
+const char kDesktopIOSPromotionTargetedEntryPoints[] =
+    "ios.desktop_ios_promo_targeted_entrypoints";
+
+// Last desktop ios promotion impression (If sms was sent it's the time of
+// sending the sms).
+const char kDesktopIOSPromotionLastImpression[] =
+    "ios.desktop_ios_promo_last_impression";
+
+// This is true when the user see the promotion, get sms, install and sign into
+// chrome ios.
+const char kDesktopIOSPromotionDone[] = "ios.desktop_ios_promo_done";
+
+}  // namespace prefs
+
+namespace desktop_ios_promotion {
+
+void RegisterDesktopPromotionUserPrefs(
+    user_prefs::PrefRegistrySyncable* registry) {
+  registry->RegisterIntegerPref(
+      prefs::kDesktopIOSPromotionSMSEntryPoint, 0,
+      user_prefs::PrefRegistrySyncable::SYNCABLE_PRIORITY_PREF);
+  registry->RegisterIntegerPref(
+      prefs::kDesktopIOSPromotionTargetedEntryPoints, 0,
+      user_prefs::PrefRegistrySyncable::SYNCABLE_PRIORITY_PREF);
+  registry->RegisterDoublePref(
+      prefs::kDesktopIOSPromotionLastImpression, 0,
+      user_prefs::PrefRegistrySyncable::SYNCABLE_PRIORITY_PREF);
+  registry->RegisterBooleanPref(
+      prefs::kDesktopIOSPromotionDone, false,
+      user_prefs::PrefRegistrySyncable::SYNCABLE_PRIORITY_PREF);
+}
+
+}  // namespace desktop_ios_promotion