--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -6,17 +6,16 @@
 
 /* A namespace class for static layout utilities. */
 
 #include "nsContentUtils.h"
 
 #include <algorithm>
 #include <math.h>
 
-#include "prprf.h"
 #include "DecoderTraits.h"
 #include "harfbuzz/hb.h"
 #include "imgICache.h"
 #include "imgIContainer.h"
 #include "imgINotificationObserver.h"
 #include "imgLoader.h"
 #include "imgRequestProxy.h"
 #include "jsapi.h"
@@ -3520,35 +3519,25 @@ nsContentUtils::ReportToConsoleNonLocali
                                      aErrorFlags, aCategory,
                                      innerWindowID);
   NS_ENSURE_SUCCESS(rv, rv);
 
   return sConsoleService->LogMessage(errorObject);
 }
 
 void
-nsContentUtils::LogMessageToConsole(const char* aMsg, ...)
+nsContentUtils::LogMessageToConsole(const char* aMsg)
 {
   if (!sConsoleService) { // only need to bother null-checking here
     CallGetService(NS_CONSOLESERVICE_CONTRACTID, &sConsoleService);
     if (!sConsoleService) {
       return;
     }
   }
-
-  va_list args;
-  va_start(args, aMsg);
-  char* formatted = PR_vsmprintf(aMsg, args);
-  va_end(args);
-  if (!formatted) {
-    return;
-  }
-
-  sConsoleService->LogStringMessage(NS_ConvertUTF8toUTF16(formatted).get());
-  PR_smprintf_free(formatted);
+  sConsoleService->LogStringMessage(NS_ConvertUTF8toUTF16(aMsg).get());
 }
 
 bool
 nsContentUtils::IsChromeDoc(nsIDocument *aDocument)
 {
   if (!aDocument) {
     return false;
   }

--- a/dom/base/nsContentUtils.h
+++ b/dom/base/nsContentUtils.h
@@ -888,18 +888,18 @@ public:
                                   const char16_t **aParams = nullptr,
                                   uint32_t aParamsLength = 0,
                                   nsIURI* aURI = nullptr,
                                   const nsAFlatString& aSourceLine
                                     = EmptyString(),
                                   uint32_t aLineNumber = 0,
                                   uint32_t aColumnNumber = 0);
 
-  static void LogMessageToConsole(const char* aMsg, ...);
-  
+  static void LogMessageToConsole(const char* aMsg);
+
   /**
    * Get the localized string named |aKey| in properties file |aFile|.
    */
   static nsresult GetLocalizedString(PropertiesFile aFile,
                                      const char* aKey,
                                      nsXPIDLString& aResult);
 
   /**

--- a/dom/workers/ServiceWorkerRegistrar.cpp
+++ b/dom/workers/ServiceWorkerRegistrar.cpp
@@ -305,18 +305,18 @@ ServiceWorkerRegistrar::ReadData()
   nsAutoCString version;
   bool hasMoreLines;
   rv = lineInputStream->ReadLine(version, &hasMoreLines);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
 
   if (!IsSupportedVersion(version)) {
-    nsContentUtils::LogMessageToConsole(
-      "Unsupported service worker registrar version: %s", version.get());
+    nsContentUtils::LogMessageToConsole(nsPrintfCString(
+      "Unsupported service worker registrar version: %s", version.get()).get());
     return NS_ERROR_FAILURE;
   }
 
   bool overwrite = false;
   while (hasMoreLines) {
     ServiceWorkerRegistrationData* entry = mData.AppendElement();
 
 #define GET_LINE(x)                                   \