[win] Fallback to registry when finding external handlers for a protocol

chrome/browser/shell_integration_win.cc

Index: chrome/browser/shell_integration_win.cc
diff --git a/chrome/browser/shell_integration_win.cc b/chrome/browser/shell_integration_win.cc
index b2bcf2997b54e28cff61ef8a37fd84f39a9699c8..6c889d3c69aa1456e54a98d444387ea11a1fc7e8 100644
--- a/chrome/browser/shell_integration_win.cc
+++ b/chrome/browser/shell_integration_win.cc
@@ -521,11 +521,15 @@ bool IsElevationNeededForSettingDefaultProtocolClient() {
 }
 
 base::string16 GetApplicationNameForProtocol(const GURL& url) {
-  // Windows 8 or above requires a new protocol association query.
-  if (base::win::GetVersion() >= base::win::VERSION_WIN8)
-    return GetAppForProtocolUsingAssocQuery(url);
-  else
-    return GetAppForProtocolUsingRegistry(url);
+  base::string16 application_name;
+  // Windows 8 or above has a new protocol association query.
+  if (base::win::GetVersion() >= base::win::VERSION_WIN8) {
+    application_name = GetAppForProtocolUsingAssocQuery(url);
+    if (!application_name.empty())
+      return application_name;
+  }
+
+  return GetAppForProtocolUsingRegistry(url);
 }
 
 DefaultWebClientState GetDefaultBrowser() {