Bug 1393201 Signed/Unsigned comparison warning in nsMIMEInfoWin.cpp - Find returns an int, not a unit r=smaug

MozReview-Commit-ID: 3qxIGFPkPXW

--HG--
extra : rebase_source : feee4c52a1b2abce64dd8213755150355c490d90

uriloader/exthandler/win/nsMIMEInfoWin.cpp

@@ -513,7 +513,7 @@ void nsMIMEInfoWin::ProcessPath(nsCOMPtr<nsIMutableArray>& appList,
   WCHAR exe[MAX_PATH+1];
   uint32_t len = GetModuleFileNameW(nullptr, exe, MAX_PATH);
   if (len < MAX_PATH && len != 0) {
-    uint32_t index = lower.Find(exe);
+    int32_t index = lower.Find(exe);
     if (index != -1)
       return;
   }