Refactor preference syncing.

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 e913cca4cee7959203bd6224f2ba225dcb38b4d5..97e8953759e71b047c3512bc58f0cf041e35b153 100644
--- a/chrome/browser/custom_handlers/protocol_handler_registry.cc
+++ b/chrome/browser/custom_handlers/protocol_handler_registry.cc
@@ -260,9 +260,12 @@ void ProtocolHandlerRegistry::OnIgnoreRegisterProtocolHandler(
 }
 
 void ProtocolHandlerRegistry::RegisterPrefs(PrefService* prefService) {
-  prefService->RegisterListPref(prefs::kRegisteredProtocolHandlers);
-  prefService->RegisterListPref(prefs::kIgnoredProtocolHandlers);
-  prefService->RegisterBooleanPref(prefs::kCustomHandlersEnabled, true);
+  prefService->RegisterListPref(prefs::kRegisteredProtocolHandlers,
+                                false /* don't sync pref */);
+  prefService->RegisterListPref(prefs::kIgnoredProtocolHandlers,
+                                false /* don't sync pref */);
+  prefService->RegisterBooleanPref(prefs::kCustomHandlersEnabled, true,
+                                   false /* don't sync pref */);
 }
 
 // Delegate --------------------------------------------------------------------