Preventing our default handlers for ChromeOS to show up or confuse the user

chrome/browser/custom_handlers/protocol_handler_registry.h

Index: chrome/browser/custom_handlers/protocol_handler_registry.h
diff --git a/chrome/browser/custom_handlers/protocol_handler_registry.h b/chrome/browser/custom_handlers/protocol_handler_registry.h
index edfb7ab6327372f319afaec84e7d5fe26b2650a6..4df4d6a0f73e3a5caacd289559f84d99afbcae76 100644
--- a/chrome/browser/custom_handlers/protocol_handler_registry.h
+++ b/chrome/browser/custom_handlers/protocol_handler_registry.h
@@ -191,6 +191,10 @@ class ProtocolHandlerRegistry
 
   bool enabled() const { return enabled_; }
 
+  // Add a predefined protocol handler. This has to be called before the first
+  // load command was issued, otherwise the command will be ignored.
+  void AddFixedHandler(const ProtocolHandler& handler);
+
  private:
   friend class base::RefCountedThreadSafe<ProtocolHandlerRegistry>;
 
@@ -277,6 +281,10 @@ class ProtocolHandlerRegistry
   // Whether or not we are loading.
   bool is_loading_;
 
+  // When the table gets loaded this flag will be set and any further calls to
+  // AddFixedHandler will be rejected.
+  bool is_loaded_;

[benwells, 2012/04/26 00:34:42]

Why is this necessary?

[Mr4D (OOO till 08-26), 2012/04/26 13:46:35]

It is a "debugging" helper: Default handlers can only be added before the load
call. After the load call they could overwrite user settings which isn't
allowed. As such a DCHECK will be used to check that this does not happen.

+
   DefaultClientObserverList default_client_observers_;
 
   // Copy of default_handlers_ that is only accessed on the IO thread.