Add Desktop iOS promotion logging to chrome ios app.

ios/chrome/browser/desktop_promotion/desktop_promotion_sync_observer.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.
+
+#import "ios/chrome/browser/desktop_promotion/desktop_promotion_sync_observer.h"
+
+#include <memory>
+
+#include "base/metrics/histogram.h"
+#include "base/strings/stringprintf.h"
+#include "base/time/time.h"
+#include "components/browser_sync/profile_sync_service.h"
+#include "components/prefs/pref_service.h"
+#include "ios/chrome/browser/browser_state/chrome_browser_state.h"
+#include "ios/chrome/browser/desktop_promotion/desktop_promotion_prefs.h"
+#include "ios/chrome/browser/sync/ios_chrome_profile_sync_service_factory.h"
+
+namespace {
+
+// Needed by UMA_HISTOGRAM_ENUM as the max value that shouldn't be exceeded.
+const int kMaxEntryPoints = 5;
+const char* kDesktopIOSPromotionEntrypointHistogramPrefix[] = {
+    "SavePasswordsNewBubble", "BookmarksNewBubble", "BookmarksExistingBubble",
+    "HistoryPage"};
+const char kSMSSentIOSSigninReasonHistogram[] =
+    "DesktopIOSPromotion.SMSSent.IOSSigninReason";
+const char kNoSMSIOSSigninReasonHistogram[] =
+    "DesktopIOSPromotion.NoSMS.IOSSigninReason";
+}
+
+DesktopPromotionSyncObserver::DesktopPromotionSyncObserver(
+    ios::ChromeBrowserState* browser_state)
+    : browser_state_(browser_state) {
+  browser_sync::ProfileSyncService* sync_service =
+      IOSChromeProfileSyncServiceFactory::GetForBrowserState(browser_state_);
+  sync_service->AddObserver(this);
+}
+
+DesktopPromotionSyncObserver::~DesktopPromotionSyncObserver() {
+  browser_sync::ProfileSyncService* sync_service =
+      IOSChromeProfileSyncServiceFactory::GetForBrowserState(browser_state_);
+  sync_service->RemoveObserver(this);
+}
+
+void DesktopPromotionSyncObserver::OnStateChanged() {
+  browser_sync::ProfileSyncService* sync_service =
+      IOSChromeProfileSyncServiceFactory::GetForBrowserState(browser_state_);
+  if (!desktop_metrics_logger_initiated_ &&
+      sync_service->GetActiveDataTypes().Has(syncer::PRIORITY_PREFERENCES)) {
+    desktop_metrics_logger_initiated_ = true;
+    PrefService* prefs = browser_state_->GetPrefs();
+    bool done_logging = prefs->GetBoolean(prefs::kDesktopIOSPromotionDone);
+    double last_impression =
+        prefs->GetDouble(prefs::kDesktopIOSPromotionLastImpression);
+    base::TimeDelta delta =
+        base::Time::Now() - base::Time::FromDoubleT(last_impression);
+    if (!done_logging && delta.InDays() < 7) {
+      // This user have seen the promotion in the last 7 days so it may be a
+      // reason of the installation.
+      int sms_entrypoint =
+          prefs->GetInteger(prefs::kDesktopIOSPromotionSMSEntryPoint);
+      int targeted_entrypoints =
+          prefs->GetInteger(prefs::kDesktopIOSPromotionTargetedEntryPoints);
+      // Entry points are represented on the preference by integers [1..4].
+      for (int i = 1; i < kMaxEntryPoints; i++) {
+        if (sms_entrypoint == i) {
+          UMA_HISTOGRAM_ENUMERATION(kSMSSentIOSSigninReasonHistogram, i,
+                                    kMaxEntryPoints);
+          UMA_HISTOGRAM_COUNTS(
+              base::StringPrintf(
+                  "DesktopIOSPromotion.%s.CompletionTime",
+                  kDesktopIOSPromotionEntrypointHistogramPrefix[i - 1]),
+              delta.InHours());
+        } else {
+          if ((1 << i) & targeted_entrypoints)
+            UMA_HISTOGRAM_ENUMERATION(kNoSMSIOSSigninReasonHistogram, i,
+                                      kMaxEntryPoints);
+        }
+      }
+      prefs->SetBoolean(prefs::kDesktopIOSPromotionDone, true);
+    }
+  }
+}