Introduce a temporary workaround to ensure tracked preferences set to empty list/dict are not confu…

chrome/browser/prefs/pref_metrics_service.cc

Index: chrome/browser/prefs/pref_metrics_service.cc
diff --git a/chrome/browser/prefs/pref_metrics_service.cc b/chrome/browser/prefs/pref_metrics_service.cc
index a4a4f33294c741b278a76ac116e2e02da40d3f0f..47eca5b09ca9dfbf7903ebe9bf0f4d93944374d7 100644
--- a/chrome/browser/prefs/pref_metrics_service.cc
+++ b/chrome/browser/prefs/pref_metrics_service.cc
@@ -287,6 +287,11 @@ void PrefMetricsService::CheckTrackedPreferences() {
     if (!prefs_->FindPreference(tracked_pref_paths_[i]))
       continue;
 
+    // Make sure tracked prefs are saved to disk even if empty.
+    // TODO(gab): Guarantee this for all prefs at a lower level and remove this
+    // hack.
+    prefs_->MarkUserStoreNeedsEmptyValue(tracked_pref_paths_[i]);

[battre, 2013/11/22 13:01:57]

I think I would move this into the constructor. Otherwise, it is executed every
time the method is executed.

[gab, 2013/11/22 18:24:37]

Done, thanks.

+
     const base::Value* value = prefs_->GetUserPrefValue(tracked_pref_paths_[i]);
     std::string last_hash;
     // First try to get the stored expected hash...