Remove unused lock, add debug-only verification of intended usage.

chrome/browser/content_settings/host_content_settings_map.cc

Index: chrome/browser/content_settings/host_content_settings_map.cc
diff --git a/chrome/browser/content_settings/host_content_settings_map.cc b/chrome/browser/content_settings/host_content_settings_map.cc
index f4ed3245bec852d4d6f070e199d46df159ff46ae..a390189bf54b156b767ce75e8850198646c90b8b 100644
--- a/chrome/browser/content_settings/host_content_settings_map.cc
+++ b/chrome/browser/content_settings/host_content_settings_map.cc
@@ -78,8 +78,11 @@ bool SupportsResourceIdentifier(ContentSettingsType content_type) {
 
 HostContentSettingsMap::HostContentSettingsMap(
     PrefService* prefs,
-    bool incognito)
-    : prefs_(prefs),
+    bool incognito) :
+#ifndef NDEBUG
+      used_content_settings_providers_(false),
+#endif
+      prefs_(prefs),
       is_off_the_record_(incognito) {
   content_settings::ObservableProvider* policy_provider =
       new content_settings::PolicyProvider(prefs_);
@@ -106,6 +109,9 @@ HostContentSettingsMap::HostContentSettingsMap(
 void HostContentSettingsMap::RegisterExtensionService(
     ExtensionService* extension_service) {
   DCHECK(extension_service);
+#ifndef NDEBUG
+  DCHECK(!used_content_settings_providers_);
+#endif
   DCHECK(!content_settings_providers_[INTERNAL_EXTENSION_PROVIDER]);
   DCHECK(!content_settings_providers_[CUSTOM_EXTENSION_PROVIDER]);
 
@@ -168,6 +174,8 @@ ContentSetting HostContentSettingsMap::GetDefaultContentSettingFromProvider(
 ContentSetting HostContentSettingsMap::GetDefaultContentSetting(
     ContentSettingsType content_type,
     std::string* provider_id) const {
+  UsedContentSettingsProviders();
+
   // Iterate through the list of providers and return the first non-NULL value
   // that matches |primary_url| and |secondary_url|.
   for (ConstProviderIterator provider = content_settings_providers_.begin();
@@ -209,6 +217,7 @@ void HostContentSettingsMap::GetSettingsForOneType(
   DCHECK(SupportsResourceIdentifier(content_type) ||
          resource_identifier.empty());
   DCHECK(settings);
+  UsedContentSettingsProviders();
 
   settings->clear();
   for (ConstProviderIterator provider = content_settings_providers_.begin();
@@ -258,6 +267,8 @@ void HostContentSettingsMap::SetWebsiteSetting(
   DCHECK(IsValueAllowedForType(prefs_, value, content_type));
   DCHECK(SupportsResourceIdentifier(content_type) ||
          resource_identifier.empty());
+  UsedContentSettingsProviders();
+
   for (ProviderIterator provider = content_settings_providers_.begin();
        provider != content_settings_providers_.end();
        ++provider) {
@@ -317,6 +328,7 @@ void HostContentSettingsMap::AddExceptionForURL(
 
 void HostContentSettingsMap::ClearSettingsForOneType(
     ContentSettingsType content_type) {
+  UsedContentSettingsProviders();
   for (ProviderIterator provider = content_settings_providers_.begin();
        provider != content_settings_providers_.end();
        ++provider) {
@@ -505,6 +517,12 @@ void HostContentSettingsMap::AddSettingsForOneType(
   }
 }
 
+void HostContentSettingsMap::UsedContentSettingsProviders() const {
+#ifndef NDEBUG
+  used_content_settings_providers_ = true;
+#endif
+}
+
 bool HostContentSettingsMap::ShouldAllowAllContent(
     const GURL& primary_url,
     const GURL& secondary_url,