Remove EmptyRuleIterators with nullptrs.

components/content_settings/core/browser/host_content_settings_map.cc

Index: components/content_settings/core/browser/host_content_settings_map.cc
diff --git a/components/content_settings/core/browser/host_content_settings_map.cc b/components/content_settings/core/browser/host_content_settings_map.cc
index 723cd51eb125f49ee13da20c0c2e8e740daecd17..130fc26c8b4d1238aa09d3e0fb428dddc663ad38 100644
--- a/components/content_settings/core/browser/host_content_settings_map.cc
+++ b/components/content_settings/core/browser/host_content_settings_map.cc
@@ -230,12 +230,14 @@ ContentSetting HostContentSettingsMap::GetDefaultContentSettingFromProvider(
   std::unique_ptr<content_settings::RuleIterator> rule_iterator(
       provider->GetRuleIterator(content_type, std::string(), false));
 
-  ContentSettingsPattern wildcard = ContentSettingsPattern::Wildcard();
-  while (rule_iterator->HasNext()) {
-    content_settings::Rule rule = rule_iterator->Next();
-    if (rule.primary_pattern == wildcard &&
-        rule.secondary_pattern == wildcard) {
-      return content_settings::ValueToContentSetting(rule.value.get());
+  if (rule_iterator) {
+    ContentSettingsPattern wildcard = ContentSettingsPattern::Wildcard();
+    while (rule_iterator->HasNext()) {
+      content_settings::Rule rule = rule_iterator->Next();
+      if (rule.primary_pattern == wildcard &&
+          rule.secondary_pattern == wildcard) {
+        return content_settings::ValueToContentSetting(rule.value.get());
+      }
     }
   }
   return CONTENT_SETTING_DEFAULT;
@@ -790,6 +792,9 @@ void HostContentSettingsMap::AddSettingsForOneType(
     bool incognito) const {
   std::unique_ptr<content_settings::RuleIterator> rule_iterator(
       provider->GetRuleIterator(content_type, resource_identifier, incognito));
+  if (!rule_iterator)
+    return;
+
   while (rule_iterator->HasNext()) {
     const content_settings::Rule& rule = rule_iterator->Next();
     ContentSetting setting_value = CONTENT_SETTING_DEFAULT;
@@ -954,15 +959,17 @@ HostContentSettingsMap::GetContentSettingValueAndPatterns(
     const GURL& secondary_url,
     ContentSettingsPattern* primary_pattern,
     ContentSettingsPattern* secondary_pattern) {
-  while (rule_iterator->HasNext()) {
-    const content_settings::Rule& rule = rule_iterator->Next();
-    if (rule.primary_pattern.Matches(primary_url) &&
-        rule.secondary_pattern.Matches(secondary_url)) {
-      if (primary_pattern)
-        *primary_pattern = rule.primary_pattern;
-      if (secondary_pattern)
-        *secondary_pattern = rule.secondary_pattern;
-      return base::WrapUnique(rule.value.get()->DeepCopy());
+  if (rule_iterator) {
+    while (rule_iterator->HasNext()) {
+      const content_settings::Rule& rule = rule_iterator->Next();
+      if (rule.primary_pattern.Matches(primary_url) &&
+          rule.secondary_pattern.Matches(secondary_url)) {
+        if (primary_pattern)
+          *primary_pattern = rule.primary_pattern;
+        if (secondary_pattern)
+          *secondary_pattern = rule.secondary_pattern;
+        return base::WrapUnique(rule.value.get()->DeepCopy());
+      }
     }
   }
   return std::unique_ptr<base::Value>();