--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -28,17 +28,16 @@
 #include "CrashReporterParent.h"
 #include "DeviceStorageStatics.h"
 #include "GMPServiceParent.h"
 #include "HandlerServiceParent.h"
 #include "IHistory.h"
 #include "imgIContainer.h"
 #if defined(XP_WIN) && defined(ACCESSIBILITY)
 #include "mozilla/a11y/AccessibleWrap.h"
-#include "mozilla/WindowsVersion.h"
 #endif
 #include "mozilla/ClearOnShutdown.h"
 #include "mozilla/StyleSheetInlines.h"
 #include "mozilla/DataStorage.h"
 #include "mozilla/devtools/HeapSnapshotTempFileHelperParent.h"
 #include "mozilla/docshell/OfflineCacheUpdateParent.h"
 #include "mozilla/dom/DataTransfer.h"
 #include "mozilla/dom/Element.h"
@@ -1052,20 +1051,18 @@ ContentParent::Init()
     obs->NotifyObservers(static_cast<nsIObserver*>(this), "ipc:content-created", cpId.get());
   }
 
 #ifdef ACCESSIBILITY
   // If accessibility is running in chrome process then start it in content
   // process.
   if (nsIPresShell::IsAccessibilityActive()) {
 #if defined(XP_WIN)
-    if (IsVistaOrLater()) {
-      Unused <<
-        SendActivateA11y(a11y::AccessibleWrap::GetContentProcessIdFor(ChildID()));
-    }
+    Unused <<
+      SendActivateA11y(a11y::AccessibleWrap::GetContentProcessIdFor(ChildID()));
 #else
     Unused << SendActivateA11y(0);
 #endif
   }
 #endif
 
 #ifdef MOZ_GECKO_PROFILER
   nsCOMPtr<nsIProfiler> profiler(do_GetService("@mozilla.org/tools/profiler;1"));
@@ -2386,20 +2383,18 @@ ContentParent::Observe(nsISupports* aSub
     Unused << SendFilePathUpdate(file->mStorageType, file->mStorageName, file->mPath, creason);
   }
 #ifdef ACCESSIBILITY
   else if (aData && !strcmp(aTopic, "a11y-init-or-shutdown")) {
     if (*aData == '1') {
       // Make sure accessibility is running in content process when
       // accessibility gets initiated in chrome process.
 #if defined(XP_WIN)
-      if (IsVistaOrLater()) {
-        Unused <<
-          SendActivateA11y(a11y::AccessibleWrap::GetContentProcessIdFor(ChildID()));
-      }
+      Unused <<
+        SendActivateA11y(a11y::AccessibleWrap::GetContentProcessIdFor(ChildID()));
 #else
       Unused << SendActivateA11y(0);
 #endif
     } else {
       // If possible, shut down accessibility in content process when
       // accessibility gets shutdown in chrome process.
       Unused << SendShutdownA11y();
     }

--- a/dom/ipc/ContentProcess.cpp
+++ b/dom/ipc/ContentProcess.cpp
@@ -3,20 +3,16 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/ipc/IOThreadChild.h"
 
 #include "ContentProcess.h"
 
-#if defined(XP_WIN) && defined(MOZ_CONTENT_SANDBOX)
-#include "mozilla/WindowsVersion.h"
-#endif
-
 #if defined(XP_MACOSX) && defined(MOZ_CONTENT_SANDBOX)
 #include <stdlib.h>
 #endif
 
 #if (defined(XP_WIN) || defined(XP_MACOSX)) && defined(MOZ_CONTENT_SANDBOX)
 #include "mozilla/Preferences.h"
 #include "nsAppDirectoryServiceDefs.h"
 #include "nsDirectoryService.h"
@@ -28,19 +24,18 @@ using mozilla::ipc::IOThreadChild;
 namespace mozilla {
 namespace dom {
 
 #if defined(XP_WIN) && defined(MOZ_CONTENT_SANDBOX)
 static bool
 IsSandboxTempDirRequired()
 {
   // On Windows, a sandbox-writable temp directory is only used
-  // for Vista or later with sandbox pref level >= 1.
-  return (IsVistaOrLater() &&
-    (Preferences::GetInt("security.sandbox.content.level") >= 1));
+  // when sandbox pref level >= 1.
+  return Preferences::GetInt("security.sandbox.content.level") >= 1;
 }
 
 static void
 SetTmpEnvironmentVariable(nsIFile* aValue)
 {
   // Save the TMP environment variable so that is is picked up by GetTempPath().
   // Note that we specifically write to the TMP variable, as that is the first
   // variable that is checked by GetTempPath() to determine its output.