--- a/dom/media/MediaManager.cpp
+++ b/dom/media/MediaManager.cpp
@@ -1848,17 +1848,17 @@ MediaManager::GetNonE10sParent()
   }
   return mNonE10sParent;
 }
 
 /* static */ void
 MediaManager::StartupInit()
 {
 #ifdef WIN32
-  if (IsVistaOrLater() && !IsWin8OrLater()) {
+  if (!IsWin8OrLater()) {
     // Bug 1107702 - Older Windows fail in GetAdaptersInfo (and others) if the
     // first(?) call occurs after the process size is over 2GB (kb/2588507).
     // Attempt to 'prime' the pump by making a call at startup.
     unsigned long out_buf_len = sizeof(IP_ADAPTER_INFO);
     PIP_ADAPTER_INFO pAdapterInfo = (IP_ADAPTER_INFO *) moz_xmalloc(out_buf_len);
     if (GetAdaptersInfo(pAdapterInfo, &out_buf_len) == ERROR_BUFFER_OVERFLOW) {
       free(pAdapterInfo);
       pAdapterInfo = (IP_ADAPTER_INFO *) moz_xmalloc(out_buf_len);

--- a/dom/media/webrtc/MediaEngineWebRTC.cpp
+++ b/dom/media/webrtc/MediaEngineWebRTC.cpp
@@ -6,19 +6,16 @@
 
 #include "nsIPrefService.h"
 #include "nsIPrefBranch.h"
 
 #include "CSFLog.h"
 #include "prenv.h"
 
 #include "mozilla/Logging.h"
-#ifdef XP_WIN
-#include "mozilla/WindowsVersion.h"
-#endif
 
 static mozilla::LazyLogModule sGetUserMediaLog("GetUserMedia");
 
 #include "MediaEngineWebRTC.h"
 #include "ImageContainer.h"
 #include "nsIComponentRegistrar.h"
 #include "MediaEngineTabVideoSource.h"
 #include "MediaEngineRemoteVideoSource.h"
@@ -264,21 +261,17 @@ MediaEngineWebRTC::EnumerateVideoDevices
   if (mHasTabVideoSource || dom::MediaSourceEnum::Browser == aMediaSource) {
     aVSources->AppendElement(new MediaEngineTabVideoSource());
   }
 }
 
 bool
 MediaEngineWebRTC::SupportsDuplex()
 {
-#ifndef XP_WIN
   return mFullDuplex;
-#else
-  return IsVistaOrLater() && mFullDuplex;
-#endif
 }
 
 void
 MediaEngineWebRTC::EnumerateAudioDevices(dom::MediaSourceEnum aMediaSource,
                                          nsTArray<RefPtr<MediaEngineAudioSource> >* aASources)
 {
   ScopedCustomReleasePtr<webrtc::VoEBase> ptrVoEBase;
   // We spawn threads to handle gUM runnables, so we must protect the member vars