Add feature flag for offline indicator

Bug: 852577
Change-Id: I092cf8b80fba521725e24425e2e110937af2e222
Reviewed-on: https://chromium-review.googlesource.com/1100010
Commit-Queue: Jian Li <jianli@chromium.org>
Reviewed-by: Peter Williamson <petewil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567389}

chrome/browser/about_flags.cc

@@ -2329,6 +2329,9 @@ const FeatureEntry kFeatureEntries[] = {
      kOsAndroid,
      FEATURE_VALUE_TYPE(
          offline_pages::kOfflinePagesShowAlternateDinoPageFeature)},
+    {"offline-indicator", flag_descriptions::kOfflineIndicatorName,
+     flag_descriptions::kOfflineIndicatorDescription, kOsAndroid,
+     FEATURE_VALUE_TYPE(offline_pages::kOfflineIndicatorFeature)},
 #endif  // OS_ANDROID
     {"disallow-doc-written-script-loads",
      flag_descriptions::kDisallowDocWrittenScriptsUiName,

chrome/browser/flag_descriptions.cc

@@ -2285,6 +2285,10 @@ const char kOfflineBookmarksName[] = "Enable offline bookmarks";
 const char kOfflineBookmarksDescription[] =
     "Enable saving bookmarked pages for offline viewing.";
 
+const char kOfflineIndicatorName[] = "Enable offline indicator";
+const char kOfflineIndicatorDescription[] =
+    "Enable showing offline indicator while offline.";
+
 const char kOfflinePagesCtName[] = "Enable Offline Pages CT features.";
 const char kOfflinePagesCtDescription[] = "Enable Offline Pages CT features.";
 

chrome/browser/flag_descriptions.h

@@ -1391,6 +1391,9 @@ extern const char kNtpGoogleGInOmniboxDescription[];
 extern const char kOfflineBookmarksName[];
 extern const char kOfflineBookmarksDescription[];
 
+extern const char kOfflineIndicatorName[];
+extern const char kOfflineIndicatorDescription[];
+
 extern const char kOfflinePagesCtName[];
 extern const char kOfflinePagesCtDescription[];
 

components/offline_pages/core/offline_page_feature.cc

@@ -76,6 +76,9 @@ const base::Feature kOfflinePagesCTSuppressNotificationsFeature{
 const base::Feature kOfflinePagesShowAlternateDinoPageFeature{
     "OfflinePagesShowAlternateDinoPage", base::FEATURE_DISABLED_BY_DEFAULT};
 
+const base::Feature kOfflineIndicatorFeature{"OfflineIndicator",
+                                             base::FEATURE_DISABLED_BY_DEFAULT};
+
 const char kPrefetchingOfflinePagesExperimentsOption[] = "exp";
 
 bool IsOfflineBookmarksEnabled() {
@@ -174,4 +177,8 @@ std::string GetPrefetchingOfflinePagesExperimentTag() {
       kPrefetchingOfflinePagesExperimentsOption);
 }
 
+bool IsOfflineIndicatorFeatureEnabled() {
+  return base::FeatureList::IsEnabled(kOfflineIndicatorFeature);
+}
+
 }  // namespace offline_pages

components/offline_pages/core/offline_page_feature.h

@@ -28,6 +28,7 @@ extern const base::Feature kOfflinePagesInDownloadHomeOpenInCctFeature;
 extern const base::Feature kOfflinePagesDescriptiveFailStatusFeature;
 extern const base::Feature kOfflinePagesCTSuppressNotificationsFeature;
 extern const base::Feature kOfflinePagesShowAlternateDinoPageFeature;
+extern const base::Feature kOfflineIndicatorFeature;
 
 // The parameter name used to find the experiment tag for prefetching offline
 // pages.
@@ -109,6 +110,9 @@ bool ShouldShowAlternateDinoPage();
 // the request.
 std::string GetPrefetchingOfflinePagesExperimentTag();
 
+// Returns true if offline indicator UI is shown when the user is offline.
+bool IsOfflineIndicatorFeatureEnabled();
+
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_FEATURE_H_

tools/metrics/histograms/enums.xml

@@ -27774,6 +27774,7 @@ from previous Chrome versions.
   <int value="19815558" label="EnableSettingsShortcutSearch:disabled"/>
   <int value="23556595" label="MarkHttpAs:enabled"/>
   <int value="27507364" label="apps-keep-chrome-alive"/>
+  <int value="29212695" label="OfflineIndicator:enabled"/>
   <int value="31848187" label="ViewsTaskManager:disabled"/>
   <int value="33778663" label="OriginTrials:enabled"/>
   <int value="37024318" label="disable-affiliation-based-matching"/>
@@ -28005,6 +28006,7 @@ from previous Chrome versions.
   <int value="582187448" label="DontPrefetchLibraries:enabled"/>
   <int value="584541349" label="ContextualSearchSingleActions:disabled"/>
   <int value="586021329" label="VibrateRequiresUserGesture:enabled"/>
+  <int value="588333474" label="OfflineIndicator:disabled"/>
   <int value="592050831" label="disable-slimming-paint"/>
   <int value="593707592" label="disable-network-portal-notification"/>
   <int value="595371145" label="OmniboxRichEntitySuggestions:disabled"/>