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

chrome/browser/custom_handlers/protocol_handler_registry.cc

Index: chrome/browser/custom_handlers/protocol_handler_registry.cc
diff --git a/chrome/browser/custom_handlers/protocol_handler_registry.cc b/chrome/browser/custom_handlers/protocol_handler_registry.cc
index d81af988fc58af5d2e7f30e6b30679ff451d30bf..46bff5db78241e4cfe41f7f66f7ab223eec60820 100644
--- a/chrome/browser/custom_handlers/protocol_handler_registry.cc
+++ b/chrome/browser/custom_handlers/protocol_handler_registry.cc
@@ -10,6 +10,7 @@
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/utf_string_conversions.h"
 #include "chrome/browser/custom_handlers/register_protocol_handler_infobar_delegate.h"
 #include "chrome/browser/net/chrome_url_request_context.h"
 #include "chrome/browser/prefs/pref_service.h"
@@ -35,7 +36,8 @@ ProtocolHandlerRegistry::ProtocolHandlerRegistry(Profile* profile,
       delegate_(delegate),
       enabled_(true),
       enabled_io_(enabled_),
-      is_loading_(false) {
+      is_loading_(false),
+      is_loaded_(false) {
 }
 
 ProtocolHandlerRegistry::~ProtocolHandlerRegistry() {
@@ -195,6 +197,8 @@ bool ShouldRemoveHandlersNotInOS() {
 } // namespace
 
 void ProtocolHandlerRegistry::Load() {
+  // Any further default additions to the table will get rejected from now on.
+  is_loaded_ = true;
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   is_loading_ = true;
   PrefService* prefs = profile_->GetPrefs();
@@ -591,6 +595,13 @@ void ProtocolHandlerRegistry::NotifyChanged() {
       content::NotificationService::NoDetails());
 }
 
+void ProtocolHandlerRegistry::AddFixedHandler(const ProtocolHandler& handler) {
+  // If called after the load command was issued this function will fail.
+  DCHECK(!is_loaded_);
+  RegisterProtocolHandler(handler);
+  SetDefault(handler);
+}
+
 // IO thread methods -----------------------------------------------------------
 
 void ProtocolHandlerRegistry::ClearDefaultIO(const std::string& scheme) {