Add timestamp to infobar for stale Previews

chrome/browser/previews/previews_infobar_delegate.cc

Index: chrome/browser/previews/previews_infobar_delegate.cc
diff --git a/chrome/browser/previews/previews_infobar_delegate.cc b/chrome/browser/previews/previews_infobar_delegate.cc
index e5947ca3c35ad4baeb0f3003794dd1bc6d61e27d..110f20885eda515966c239a227430ac53c795f2d 100644
--- a/chrome/browser/previews/previews_infobar_delegate.cc
+++ b/chrome/browser/previews/previews_infobar_delegate.cc
@@ -4,9 +4,15 @@
 
 #include "chrome/browser/previews/previews_infobar_delegate.h"
 
+#include "base/feature_list.h"
+#include "base/metrics/field_trial_params.h"
 #include "base/metrics/histogram.h"
 #include "base/optional.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/android/android_theme_resources.h"
+#include "chrome/browser/browser_process.h"
 #include "chrome/browser/infobars/infobar_service.h"
 #include "chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings.h"
 #include "chrome/browser/net/spdyproxy/data_reduction_proxy_chrome_settings_factory.h"
@@ -16,6 +22,8 @@
 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_service.h"
 #include "components/data_reduction_proxy/core/common/data_reduction_proxy_params.h"
 #include "components/infobars/core/infobar.h"
+#include "components/network_time/network_time_tracker.h"
+#include "components/previews/core/previews_features.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_contents.h"
 #include "ui/base/l10n/l10n_util.h"
@@ -101,6 +109,7 @@ PreviewsInfoBarDelegate::~PreviewsInfoBarDelegate() {
 void PreviewsInfoBarDelegate::Create(
     content::WebContents* web_contents,
     previews::PreviewsType previews_type,
+    base::Time previews_freshness,
     bool is_data_saver_user,
     const OnDismissPreviewsInfobarCallback& on_dismiss_callback) {
   PreviewsInfoBarTabHelper* infobar_tab_helper =
@@ -116,7 +125,8 @@ void PreviewsInfoBarDelegate::Create(
     return;
 
   std::unique_ptr<PreviewsInfoBarDelegate> delegate(new PreviewsInfoBarDelegate(
-      web_contents, previews_type, is_data_saver_user, on_dismiss_callback));
+      web_contents, previews_type, previews_freshness, is_data_saver_user,
+      on_dismiss_callback));
 
 #if defined(OS_ANDROID)
   std::unique_ptr<infobars::InfoBar> infobar_ptr(
@@ -144,10 +154,12 @@ void PreviewsInfoBarDelegate::Create(
 PreviewsInfoBarDelegate::PreviewsInfoBarDelegate(
     content::WebContents* web_contents,
     previews::PreviewsType previews_type,
+    base::Time previews_freshness,
     bool is_data_saver_user,
     const OnDismissPreviewsInfobarCallback& on_dismiss_callback)
     : ConfirmInfoBarDelegate(),
       previews_type_(previews_type),
+      previews_freshness_(previews_freshness),
       infobar_dismissed_action_(INFOBAR_DISMISSED_BY_TAB_CLOSURE),
       message_text_(l10n_util::GetStringUTF16(
           is_data_saver_user ? IDS_PREVIEWS_INFOBAR_SAVED_DATA_TITLE
@@ -180,7 +192,18 @@ void PreviewsInfoBarDelegate::InfoBarDismissed() {
 }
 
 base::string16 PreviewsInfoBarDelegate::GetMessageText() const {
+// Android has a custom infobar that calls GetTimestampText() and adds the
+// timestamp in a separate description view. Other OS's can enable previews
+// for debugging purposes and don't have a custom infobar with a description
+// view, so the timestamp should be appended to the message.
+#if defined(OS_ANDROID)
   return message_text_;
+#else
+  base::string16 timestamp = GetTimestampText();
+  if (timestamp.empty())
+    return message_text_;
+  return message_text_ + base::ASCIIToUTF16(" ") + timestamp;
+#endif
 }
 
 int PreviewsInfoBarDelegate::GetButtons() const {
@@ -214,5 +237,48 @@ bool PreviewsInfoBarDelegate::LinkClicked(WindowOpenDisposition disposition) {
 }
 
 base::string16 PreviewsInfoBarDelegate::GetTimestampText() const {
-  return base::string16();
+  if (previews_freshness_.is_null())
+    return base::string16();
+  if (!base::FeatureList::IsEnabled(
+          previews::features::kStalePreviewsTimestamp)) {
+    return base::string16();
+  }
+
+  int min_staleness_in_minutes = base::GetFieldTrialParamByFeatureAsInt(
+      previews::features::kStalePreviewsTimestamp, "min_staleness_in_minutes",
+      0);
+  int max_staleness_in_minutes = base::GetFieldTrialParamByFeatureAsInt(
+      previews::features::kStalePreviewsTimestamp, "max_staleness_in_minutes",
+      0);
+
+  if (min_staleness_in_minutes == 0 || max_staleness_in_minutes == 0)
+    return base::string16();
+
+  base::Time network_time;
+  if (g_browser_process->network_time_tracker()->GetNetworkTime(&network_time,
+                                                                nullptr) !=
+      network_time::NetworkTimeTracker::NETWORK_TIME_AVAILABLE) {
+    // When network time has not been initialized yet, simply rely on the
+    // machine's current time.
+    network_time = base::Time::Now();
+  }
+
+  int staleness_in_minutes = (network_time - previews_freshness_).InMinutes();
+  // TODO(megjablon): record metrics for out of bounds staleness.
+  if (staleness_in_minutes < min_staleness_in_minutes)
+    return base::string16();
+  if (staleness_in_minutes > max_staleness_in_minutes)
+    return base::string16();
+
+  if (staleness_in_minutes < 60) {
+    return l10n_util::GetStringFUTF16(
+        IDS_PREVIEWS_INFOBAR_TIMESTAMP_MINUTES,
+        base::IntToString16(staleness_in_minutes));
+  } else if (staleness_in_minutes < 120) {
+    return l10n_util::GetStringUTF16(IDS_PREVIEWS_INFOBAR_TIMESTAMP_ONE_HOUR);
+  } else {
+    return l10n_util::GetStringFUTF16(
+        IDS_PREVIEWS_INFOBAR_TIMESTAMP_HOURS,
+        base::IntToString16(staleness_in_minutes / 60));
+  }
 }