Add a global on/off switch for content settings and expose a toggle on the Website Settings options…

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 52560a9e46a3bff54f09c7d8b414a57781b77044..79da55d1a8d03edfb6bb7e18a05b7189750be9e1 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -990,6 +990,11 @@ const char kUseCustomChromeFrame[] = "browser.custom_chrome_frame";
 // Dictionary of content settings applied to all hosts by default.
 const char kDefaultContentSettings[] = "profile.default_content_settings";
 
+// Dictionary of content settings that can globally disallow all hosts by
+// default. If a value is set, it means the setting is globally disallowed.
+// If a value is not set, it means the setting is allowed.
+const char kOverrideContentSettings[] = "profile.override_content_settings";
+
 // Boolean indicating whether the clear on exit pref was migrated to content
 // settings yet.
 const char kContentSettingsClearOnExitMigrated[] =