Ensure that --disable-extensions disables extension prefs from being enacted

chrome/browser/extensions/extension_prefs.cc

Index: chrome/browser/extensions/extension_prefs.cc
diff --git a/chrome/browser/extensions/extension_prefs.cc b/chrome/browser/extensions/extension_prefs.cc
index 94af184ad2ab6f425ad4f72453a40049ec94fe4c..52b10fd2e0be05c9d8b483fc2847af3c6cc7311b 100644
--- a/chrome/browser/extensions/extension_prefs.cc
+++ b/chrome/browser/extensions/extension_prefs.cc
@@ -227,14 +227,15 @@ std::string JoinPrefs(std::string parent, const char* child) {
 ExtensionPrefs::ExtensionPrefs(
     PrefService* prefs,
     const FilePath& root_dir,
-    ExtensionPrefValueMap* extension_pref_value_map)
+    ExtensionPrefValueMap* extension_pref_value_map,
+    bool extensions_disabled)
     : prefs_(prefs),
       install_directory_(root_dir),
       extension_pref_value_map_(extension_pref_value_map),
       content_settings_store_(new ExtensionContentSettingsStore()) {
   MakePathsRelative();
 
-  InitPrefStore();
+  InitPrefStore(extensions_disabled);
 
   content_settings_store_->AddObserver(this);
 }
@@ -1519,7 +1520,12 @@ const DictionaryValue* ExtensionPrefs::GetExtensionControlledPrefs(
   return preferences;
 }
 
-void ExtensionPrefs::InitPrefStore() {
+void ExtensionPrefs::InitPrefStore(bool extensions_disabled) {
+  if (extensions_disabled) {
+    extension_pref_value_map_->NotifyInitializationCompleted();
+    return;
+  }
+
   // When this is called, the PrefService is initialized and provides access
   // to the user preferences stored in a JSON file.
   ExtensionIdSet extension_ids;