Write last_modified date to Content Settings in the PrefProvider

components/content_settings/core/browser/content_settings_origin_identifier_value_map.cc

Index: components/content_settings/core/browser/content_settings_origin_identifier_value_map.cc
diff --git a/components/content_settings/core/browser/content_settings_origin_identifier_value_map.cc b/components/content_settings/core/browser/content_settings_origin_identifier_value_map.cc
index 3f6133b67a8cb760ad7fb12b8d5c3c8ec5633a74..c52103eded9ad49f845ef93314aa3182e3cf06dd 100644
--- a/components/content_settings/core/browser/content_settings_origin_identifier_value_map.cc
+++ b/components/content_settings/core/browser/content_settings_origin_identifier_value_map.cc
@@ -38,10 +38,11 @@ class RuleIteratorImpl : public RuleIterator {
 
   Rule Next() override {
     DCHECK(HasNext());
-    DCHECK(current_rule_->second.get());
+    DCHECK(current_rule_->second.value.get());
     Rule to_return(current_rule_->first.primary_pattern,
                    current_rule_->first.secondary_pattern,
-                   current_rule_->second.get()->DeepCopy());
+                   current_rule_->second.last_modified,
+                   current_rule_->second.value.get()->DeepCopy());
     ++current_rule_;
     return to_return;
   }
@@ -83,6 +84,10 @@ bool OriginIdentifierValueMap::PatternPair::operator<(
          std::tie(other.primary_pattern, other.secondary_pattern);
 }
 
+OriginIdentifierValueMap::ValueEntry::ValueEntry() : last_modified(), value(){};
+
+OriginIdentifierValueMap::ValueEntry::~ValueEntry(){};
+
 std::unique_ptr<RuleIterator> OriginIdentifierValueMap::GetRuleIterator(
     ContentSettingsType content_type,
     const ResourceIdentifier& resource_identifier,
@@ -129,7 +134,7 @@ base::Value* OriginIdentifierValueMap::GetValue(
   for (const auto& entry : it->second) {
     if (entry.first.primary_pattern.Matches(primary_url) &&
         entry.first.secondary_pattern.Matches(secondary_url)) {
-      return entry.second.get();
+      return entry.second.value.get();
     }
   }
   return nullptr;
@@ -140,6 +145,7 @@ void OriginIdentifierValueMap::SetValue(
     const ContentSettingsPattern& secondary_pattern,
     ContentSettingsType content_type,
     const ResourceIdentifier& resource_identifier,
+    base::Time last_modified,
     base::Value* value) {
   DCHECK(primary_pattern.IsValid());
   DCHECK(secondary_pattern.IsValid());
@@ -150,7 +156,8 @@ void OriginIdentifierValueMap::SetValue(
   EntryMapKey key(content_type, resource_identifier);
   PatternPair patterns(primary_pattern, secondary_pattern);
   // This will create the entry and the linked_ptr if needed.
-  entries_[key][patterns].reset(value);
+  entries_[key][patterns].value.reset(value);
+  entries_[key][patterns].last_modified = last_modified;
 }
 
 void OriginIdentifierValueMap::DeleteValue(