Calls to rph updating existing handlers are ignored.

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 2e75d8d21196424546aab41b69e74fe367a776de..70f0ca37bbb3cb2676613925ea85f17c327f989e 100644
--- a/chrome/browser/custom_handlers/protocol_handler_registry.cc
+++ b/chrome/browser/custom_handlers/protocol_handler_registry.cc
@@ -84,7 +84,7 @@ void ProtocolHandlerRegistry::RegisterProtocolHandler(
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(CanSchemeBeOverridden(handler.protocol()));
   DCHECK(!handler.IsEmpty());
-  if (HasRegisteredEquivalent(handler)) {
+  if (IsRegistered(handler)) {
     return;
   }
   if (enabled_ && !delegate_->IsExternalHandlerRegistered(handler.protocol()))
@@ -428,6 +428,20 @@ Value* ProtocolHandlerRegistry::EncodeIgnoredHandlers() {
   return handlers;
 }
 
+bool ProtocolHandlerRegistry::SilentlyHandleRegisterHandlerRequest(
+    const ProtocolHandler& handler) {
+  if (handler.IsEmpty() || !CanSchemeBeOverridden(handler.protocol()))
+    return true;
+
+  if (!enabled() || IsRegistered(handler) || HasIgnoredEquivalent(handler))
+    return true;
+
+  if (AttemptReplace(handler))
+    return true;
+
+  return false;
+}
+
 void ProtocolHandlerRegistry::OnAcceptRegisterProtocolHandler(
     const ProtocolHandler& handler) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));