Fix some DCHECKS when using BrowserPlugin for extension mime type handlers

chrome/browser/extensions/plugin_manager.h

Index: chrome/browser/extensions/plugin_manager.h
diff --git a/chrome/browser/extensions/plugin_manager.h b/chrome/browser/extensions/plugin_manager.h
index ea988f560634a54428d08e6e0e7e80380476bb2a..56eb9f7eb51cd05ae156d79caac76d294a4cfc43 100644
--- a/chrome/browser/extensions/plugin_manager.h
+++ b/chrome/browser/extensions/plugin_manager.h
@@ -44,9 +44,6 @@ class PluginManager : public BrowserContextKeyedAPI,
   void RegisterNaClModule(const NaClModuleInfo& info);
   void UnregisterNaClModule(const NaClModuleInfo& info);
 
-  void RegisterMimeTypeHandler(const std::string& extension_id);
-  void UnregisterMimeTypeHandler(const std::string& extension_id);
-
   // Call UpdatePluginListWithNaClModules() after registering or unregistering
   // a NaCl module to see those changes reflected in the PluginList.
   void UpdatePluginListWithNaClModules();
@@ -67,10 +64,6 @@ class PluginManager : public BrowserContextKeyedAPI,
 
   extensions::NaClModuleInfo::List nacl_module_list_;
 
-  // The set of extensions that are registered as the handler for at least one
-  // MIME type.
-  std::set<std::string> mime_type_handler_extension_ids_;
-
   Profile* profile_;
 
   // Listen to extension load, unloaded notifications.