diff --git a/dom/xhr/XMLHttpRequestMainThread.cpp b/dom/xhr/XMLHttpRequestMainThread.cpp
index b43305b236d2..dc98ca03f922 100644
--- a/dom/xhr/XMLHttpRequestMainThread.cpp
+++ b/dom/xhr/XMLHttpRequestMainThread.cpp
@@ -4175,12 +4175,12 @@ nsresult ArrayBufferBuilder::MapToFileInPackage(const nsCString& aFile,
     uint32_t offset = zip->GetDataOffset(zipItem);
     uint32_t size = zipItem->RealSize();
     mozilla::AutoFDClose pr_fd;
-    rv = aJarFile->OpenNSPRFileDesc(PR_RDONLY, 0, &pr_fd.rwget());
+    rv = aJarFile->OpenNSPRFileDesc(PR_RDONLY, 0, getter_Transfers(pr_fd));
     if (NS_FAILED(rv)) {
       return rv;
     }
     mMapPtr = JS::CreateMappedArrayBufferContents(
-        PR_FileDesc2NativeHandle(pr_fd), offset, size);
+        PR_FileDesc2NativeHandle(pr_fd.get()), offset, size);
     if (mMapPtr) {
       mLength = size;
       return NS_OK;
diff --git a/js/xpconnect/loader/AutoMemMap.cpp b/js/xpconnect/loader/AutoMemMap.cpp
index 424a8b42dd16..7ce26a9a3373 100644
--- a/js/xpconnect/loader/AutoMemMap.cpp
+++ b/js/xpconnect/loader/AutoMemMap.cpp
@@ -34,7 +34,7 @@ Result<Ok, nsresult> AutoMemMap::init(nsIFile* file, int flags, int mode,
                                       PRFileMapProtect prot) {
   MOZ_ASSERT(!fd);
 
-  MOZ_TRY(file->OpenNSPRFileDesc(flags, mode, &fd.rwget()));
+  MOZ_TRY(file->OpenNSPRFileDesc(flags, mode, getter_Transfers(fd)));
 
   return initInternal(prot);
 }
@@ -48,7 +48,7 @@ Result<Ok, nsresult> AutoMemMap::init(const FileDescriptor& file,
 
   auto handle = file.ClonePlatformHandle();
 
-  fd = PR_ImportFile(PROsfd(handle.get()));
+  fd.reset(PR_ImportFile(PROsfd(handle.get())));
   if (!fd) {
     return Err(NS_ERROR_FAILURE);
   }
@@ -79,7 +79,7 @@ Result<Ok, nsresult> AutoMemMap::initInternal(PRFileMapProtect prot,
     size_ = fileInfo.size;
   }
 
-  fileMap = PR_CreateFileMap(fd, 0, prot);
+  fileMap = PR_CreateFileMap(fd.get(), 0, prot);
   if (!fileMap) {
     return Err(NS_ERROR_FAILURE);
   }
@@ -151,7 +151,7 @@ void AutoMemMap::reset() {
     handle_ = nullptr;
   }
 #endif
-  fd.dispose();
+  fd = nullptr;
 }
 
 }  // namespace loader
diff --git a/js/xpconnect/loader/ScriptPreloader.cpp b/js/xpconnect/loader/ScriptPreloader.cpp
index 9520fb3b370c..11a71ac68ab8 100644
--- a/js/xpconnect/loader/ScriptPreloader.cpp
+++ b/js/xpconnect/loader/ScriptPreloader.cpp
@@ -712,9 +712,10 @@ Result<Ok, nsresult> ScriptPreloader::WriteCache() {
   }
 
   {
-    AutoFDClose fd;
+    AutoFDClose raiiFd;
     MOZ_TRY(cacheFile->OpenNSPRFileDesc(PR_WRONLY | PR_CREATE_FILE, 0644,
-                                        &fd.rwget()));
+                                        getter_Transfers(raiiFd)));
+    const auto fd = raiiFd.get();
 
     // We also need to hold mMonitor while we're touching scripts in
     // mScripts, or they may be freed before we're done with them.
diff --git a/js/xpconnect/loader/URLPreloader.cpp b/js/xpconnect/loader/URLPreloader.cpp
index 695f524d42a0..ad7354e5a0ff 100644
--- a/js/xpconnect/loader/URLPreloader.cpp
+++ b/js/xpconnect/loader/URLPreloader.cpp
@@ -222,9 +222,10 @@ Result<Ok, nsresult> URLPreloader::WriteCache() {
   }
 
   {
-    AutoFDClose fd;
+    AutoFDClose raiiFd;
     MOZ_TRY(cacheFile->OpenNSPRFileDesc(PR_WRONLY | PR_CREATE_FILE, 0644,
-                                        &fd.rwget()));
+                                        getter_Transfers(raiiFd)));
+    const auto fd = raiiFd.get();
 
     nsTArray<URLEntry*> entries;
     for (const auto& entry : mCachedURLs.Values()) {
diff --git a/modules/libjar/nsZipArchive.cpp b/modules/libjar/nsZipArchive.cpp
index 9ab949c89561..e0ca373e493f 100644
--- a/modules/libjar/nsZipArchive.cpp
+++ b/modules/libjar/nsZipArchive.cpp
@@ -190,13 +190,13 @@ nsresult nsZipHandle::Init(nsIFile* file, nsZipHandle** ret, PRFileDesc** aFd) {
   flags |= nsIFile::OS_READAHEAD;
 #endif
   LOG(("ZipHandle::Init %s", file->HumanReadablePath().get()));
-  nsresult rv = file->OpenNSPRFileDesc(flags, 0000, &fd.rwget());
+  nsresult rv = file->OpenNSPRFileDesc(flags, 0000, getter_Transfers(fd));
   if (NS_FAILED(rv)) return rv;
 
-  int64_t size = PR_Available64(fd);
+  int64_t size = PR_Available64(fd.get());
   if (size >= INT32_MAX) return NS_ERROR_FILE_TOO_BIG;
 
-  PRFileMap* map = PR_CreateFileMap(fd, size, PR_PROT_READONLY);
+  PRFileMap* map = PR_CreateFileMap(fd.get(), size, PR_PROT_READONLY);
   if (!map) return NS_ERROR_FAILURE;
 
   uint8_t* buf = (uint8_t*)PR_MemMap(map, 0, (uint32_t)size);
@@ -216,10 +216,10 @@ nsresult nsZipHandle::Init(nsIFile* file, nsZipHandle** ret, PRFileDesc** aFd) {
 
 #if defined(XP_WIN)
   if (aFd) {
-    *aFd = fd.forget();
+    *aFd = fd.release();
   }
 #else
-  handle->mNSPRFileDesc = fd.forget();
+  handle->mNSPRFileDesc = std::move(fd);
 #endif
   handle->mFile.Init(file);
   handle->mTotalLen = (uint32_t)size;
@@ -344,7 +344,7 @@ nsresult nsZipHandle::GetNSPRFileDesc(PRFileDesc** aNSPRFileDesc) {
     return NS_ERROR_ILLEGAL_VALUE;
   }
 
-  *aNSPRFileDesc = mNSPRFileDesc;
+  *aNSPRFileDesc = mNSPRFileDesc.get();
   if (!mNSPRFileDesc) {
     return NS_ERROR_NOT_AVAILABLE;
   }
@@ -387,7 +387,8 @@ already_AddRefed<nsZipArchive> nsZipArchive::OpenArchive(nsIFile* aFile) {
   RefPtr<nsZipHandle> handle;
 #if defined(XP_WIN)
   mozilla::AutoFDClose fd;
-  nsresult rv = nsZipHandle::Init(aFile, getter_AddRefs(handle), &fd.rwget());
+  nsresult rv =
+      nsZipHandle::Init(aFile, getter_AddRefs(handle), getter_Transfers(fd));
 #else
   nsresult rv = nsZipHandle::Init(aFile, getter_AddRefs(handle));
 #endif
diff --git a/netwerk/protocol/res/ExtensionProtocolHandler.cpp b/netwerk/protocol/res/ExtensionProtocolHandler.cpp
index 4f56578100cc..d3b1a3916452 100644
--- a/netwerk/protocol/res/ExtensionProtocolHandler.cpp
+++ b/netwerk/protocol/res/ExtensionProtocolHandler.cpp
@@ -186,15 +186,16 @@ class ExtensionJARFileOpener final : public nsISupports {
     MOZ_ASSERT(winFile);
     if (NS_SUCCEEDED(rv)) {
       rv = winFile->OpenNSPRFileDescShareDelete(PR_RDONLY, 0,
-                                                &prFileDesc.rwget());
+                                                getter_Transfers(prFileDesc));
     }
 #else
-    nsresult rv = mFile->OpenNSPRFileDesc(PR_RDONLY, 0, &prFileDesc.rwget());
+    nsresult rv =
+        mFile->OpenNSPRFileDesc(PR_RDONLY, 0, getter_Transfers(prFileDesc));
 #endif /* XP_WIN */
 
     if (NS_SUCCEEDED(rv)) {
       mFD = FileDescriptor(FileDescriptor::PlatformHandleType(
-          PR_FileDesc2NativeHandle(prFileDesc)));
+          PR_FileDesc2NativeHandle(prFileDesc.get())));
     }
 
     nsCOMPtr<nsIRunnable> event =
diff --git a/startupcache/StartupCache.cpp b/startupcache/StartupCache.cpp
index 02744d34d251..9c066a195123 100644
--- a/startupcache/StartupCache.cpp
+++ b/startupcache/StartupCache.cpp
@@ -522,9 +522,10 @@ Result<Ok, nsresult> StartupCache::WriteToDisk() {
     return Err(NS_ERROR_UNEXPECTED);
   }
 
-  AutoFDClose fd;
+  AutoFDClose raiiFd;
   MOZ_TRY(mFile->OpenNSPRFileDesc(PR_WRONLY | PR_CREATE_FILE | PR_TRUNCATE,
-                                  0644, &fd.rwget()));
+                                  0644, getter_Transfers(raiiFd)));
+  const auto fd = raiiFd.get();
 
   nsTArray<StartupCacheEntry::KeyValuePair> entries(mTable.count());
   for (auto iter = mTable.iter(); !iter.done(); iter.next()) {
diff --git a/toolkit/components/backgroundhangmonitor/HangDetails.cpp b/toolkit/components/backgroundhangmonitor/HangDetails.cpp
index b52f753f0ceb..de6ee056f6f3 100644
--- a/toolkit/components/backgroundhangmonitor/HangDetails.cpp
+++ b/toolkit/components/backgroundhangmonitor/HangDetails.cpp
@@ -10,6 +10,7 @@
 #include "nsPrintfCString.h"
 #include "js/Array.h"               // JS::NewArrayObject
 #include "js/PropertyAndElement.h"  // JS_DefineElement
+#include "mozilla/FileUtils.h"
 #include "mozilla/gfx/GPUParent.h"
 #include "mozilla/dom/ContentChild.h"
 #include "mozilla/dom/ContentParent.h"  // For RemoteTypePrefix
@@ -576,8 +577,10 @@ Result<Ok, nsresult> ReadEntry(PRFileDesc* aFile, HangStack& aStack) {
 }
 
 Result<HangDetails, nsresult> ReadHangDetailsFromFile(nsIFile* aFile) {
-  AutoFDClose fd;
-  nsresult rv = aFile->OpenNSPRFileDesc(PR_RDONLY, 0644, &fd.rwget());
+  AutoFDClose raiiFd;
+  nsresult rv =
+      aFile->OpenNSPRFileDesc(PR_RDONLY, 0644, getter_Transfers(raiiFd));
+  const auto fd = raiiFd.get();
   if (NS_FAILED(rv)) {
     return Err(rv);
   }
@@ -650,9 +653,11 @@ Result<Ok, nsresult> WriteHangDetailsToFile(HangDetails& aDetails,
     return Err(NS_ERROR_INVALID_POINTER);
   }
 
-  AutoFDClose fd;
+  AutoFDClose raiiFd;
   nsresult rv = aFile->OpenNSPRFileDesc(
-      PR_WRONLY | PR_CREATE_FILE | PR_TRUNCATE, 0644, &fd.rwget());
+      PR_WRONLY | PR_CREATE_FILE | PR_TRUNCATE, 0644, getter_Transfers(raiiFd));
+  const auto fd = raiiFd.get();
+
   if (NS_FAILED(rv)) {
     return Err(rv);
   }
diff --git a/toolkit/xre/nsAppRunner.cpp b/toolkit/xre/nsAppRunner.cpp
index 90827be7b17c..495f3bc2fd6b 100644
--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -4553,7 +4553,7 @@ bool XREMain::CheckLastStartupWasCrash() {
   // the startup crash detection window.
   AutoFDClose fd;
   Unused << crashFile.inspect()->OpenNSPRFileDesc(
-      PR_WRONLY | PR_CREATE_FILE | PR_EXCL, 0666, &fd.rwget());
+      PR_WRONLY | PR_CREATE_FILE | PR_EXCL, 0666, getter_Transfers(fd));
   return !fd;
 }
 
diff --git a/widget/LSBUtils.cpp b/widget/LSBUtils.cpp
index 38a02b758b00..9ebffacd7ef8 100644
--- a/widget/LSBUtils.cpp
+++ b/widget/LSBUtils.cpp
@@ -122,7 +122,7 @@ bool GetLSBRelease(nsACString& aDistributor, nsACString& aDescription,
   }
 
   char dist[256], desc[256], release[256], codename[256];
-  if (fscanf(stream,
+  if (fscanf(stream.get(),
              "Distributor ID:\t%255[^\n]\n"
              "Description:\t%255[^\n]\n"
              "Release:\t%255[^\n]\n"
diff --git a/widget/gtk/nsSound.cpp b/widget/gtk/nsSound.cpp
index f25a9e9274d6..0530c7322410 100644
--- a/widget/gtk/nsSound.cpp
+++ b/widget/gtk/nsSound.cpp
@@ -268,7 +268,7 @@ NS_IMETHODIMP nsSound::OnStreamComplete(nsIStreamLoader* aLoader,
 
   mozilla::AutoFDClose fd;
   rv = canberraFile->OpenNSPRFileDesc(PR_WRONLY, PR_IRUSR | PR_IWUSR,
-                                      &fd.rwget());
+                                      getter_Transfers(fd));
   if (NS_FAILED(rv)) {
     return rv;
   }
@@ -276,7 +276,7 @@ NS_IMETHODIMP nsSound::OnStreamComplete(nsIStreamLoader* aLoader,
   // XXX: Should we do this on another thread?
   uint32_t length = dataLen;
   while (length > 0) {
-    int32_t amount = PR_Write(fd, data, length);
+    int32_t amount = PR_Write(fd.get(), data, length);
     if (amount < 0) {
       return NS_ERROR_FAILURE;
     }
diff --git a/xpcom/base/Logging.cpp b/xpcom/base/Logging.cpp
index fa1527346561..61899b77c763 100644
--- a/xpcom/base/Logging.cpp
+++ b/xpcom/base/Logging.cpp
@@ -176,14 +176,14 @@ bool LimitFileToLessThanSize(const char* aFilename, uint32_t aSize,
       return false;
     }
 
-    if (fseek(file, 0, SEEK_END)) {
+    if (fseek(file.get(), 0, SEEK_END)) {
       // If we can't seek for some reason, better to just not limit the log at
       // all and hope to sort out large logs upon further analysis.
       return false;
     }
 
     // `ftell` returns a positive `long`, which might be more than 32 bits.
-    uint64_t fileSize = static_cast<uint64_t>(ftell(file));
+    uint64_t fileSize = static_cast<uint64_t>(ftell(file.get()));
 
     if (fileSize <= aSize) {
       return true;
@@ -192,7 +192,7 @@ bool LimitFileToLessThanSize(const char* aFilename, uint32_t aSize,
     uint64_t minBytesToDrop = fileSize - aSize;
     uint64_t numBytesDropped = 0;
 
-    if (fseek(file, 0, SEEK_SET)) {
+    if (fseek(file.get(), 0, SEEK_SET)) {
       // Same as above: if we can't seek, hope for the best.
       return false;
     }
@@ -250,11 +250,12 @@ bool LimitFileToLessThanSize(const char* aFilename, uint32_t aSize,
     // `fgets` always null terminates.  If the line is too long, it won't
     // include a trailing '\n' but will be null-terminated.
     UniquePtr<char[]> line = MakeUnique<char[]>(aLongLineSize + 1);
-    while (fgets(line.get(), aLongLineSize + 1, file)) {
+    while (fgets(line.get(), aLongLineSize + 1, file.get())) {
       if (numBytesDropped >= minBytesToDrop) {
-        if (fputs(line.get(), temp) < 0) {
+        if (fputs(line.get(), temp.get()) < 0) {
           NS_WARNING(
-              nsPrintfCString("fputs failed: ferror %d\n", ferror(temp)).get());
+              nsPrintfCString("fputs failed: ferror %d\n", ferror(temp.get()))
+                  .get());
           failedToWrite = true;
           break;
         }
diff --git a/xpcom/build/FileLocation.cpp b/xpcom/build/FileLocation.cpp
index bb090c2b94d0..5162546f1d49 100644
--- a/xpcom/build/FileLocation.cpp
+++ b/xpcom/build/FileLocation.cpp
@@ -8,6 +8,8 @@
 #include "nsZipArchive.h"
 #include "nsURLHelper.h"
 
+#include "mozilla/UniquePtrExtensions.h"
+
 namespace mozilla {
 
 FileLocation::FileLocation() = default;
@@ -147,7 +149,8 @@ bool FileLocation::Equals(const FileLocation& aFile) const {
 
 nsresult FileLocation::GetData(Data& aData) {
   if (!IsZip()) {
-    return mBaseFile->OpenNSPRFileDesc(PR_RDONLY, 0444, &aData.mFd.rwget());
+    return mBaseFile->OpenNSPRFileDesc(PR_RDONLY, 0444,
+                                       getter_Transfers(aData.mFd));
   }
   aData.mZip = mBaseZip;
   if (!aData.mZip) {
@@ -166,7 +169,7 @@ nsresult FileLocation::GetData(Data& aData) {
 nsresult FileLocation::Data::GetSize(uint32_t* aResult) {
   if (mFd) {
     PRFileInfo64 fileInfo;
-    if (PR_SUCCESS != PR_GetOpenFileInfo64(mFd, &fileInfo)) {
+    if (PR_SUCCESS != PR_GetOpenFileInfo64(mFd.get(), &fileInfo)) {
       return NS_ErrorAccordingToNSPR();
     }
 
@@ -187,7 +190,7 @@ nsresult FileLocation::Data::GetSize(uint32_t* aResult) {
 nsresult FileLocation::Data::Copy(char* aBuf, uint32_t aLen) {
   if (mFd) {
     for (uint32_t totalRead = 0; totalRead < aLen;) {
-      int32_t read = PR_Read(mFd, aBuf + totalRead,
+      int32_t read = PR_Read(mFd.get(), aBuf + totalRead,
                              XPCOM_MIN(aLen - totalRead, uint32_t(INT32_MAX)));
       if (read < 0) {
         return NS_ErrorAccordingToNSPR();
diff --git a/xpcom/glue/FileUtils.h b/xpcom/glue/FileUtils.h
index 6b322fb83988..8e66ee5860ee 100644
--- a/xpcom/glue/FileUtils.h
+++ b/xpcom/glue/FileUtils.h
@@ -17,7 +17,7 @@
 #include "prio.h"
 #include "prlink.h"
 
-#include "mozilla/Scoped.h"
+#include <memory>  // unique_ptr
 #include "nsIFile.h"
 #include <errno.h>
 #include <limits.h>
@@ -32,51 +32,26 @@ typedef int filedesc_t;
 typedef const char* pathstr_t;
 #endif
 
-/**
- * ScopedCloseFD is a RAII wrapper for POSIX file descriptors
- *
- * Instances |close()| their fds when they go out of scope.
- */
-struct ScopedCloseFDTraits {
-  typedef int type;
-  static type empty() { return -1; }
-  static void release(type aFd) {
-    if (aFd != -1) {
-      close(aFd);
-    }
-  }
-};
-typedef Scoped<ScopedCloseFDTraits> ScopedClose;
-
 #if defined(MOZILLA_INTERNAL_API)
 
-/**
- * AutoFDClose is a RAII wrapper for PRFileDesc.
- *
- * Instances |PR_Close| their fds when they go out of scope.
- **/
-struct ScopedClosePRFDTraits {
-  typedef PRFileDesc* type;
-  static type empty() { return nullptr; }
-  static void release(type aFd) {
+struct PRCloseDeleter {
+  void operator()(PRFileDesc* aFd) {
     if (aFd) {
       PR_Close(aFd);
     }
   }
 };
-typedef Scoped<ScopedClosePRFDTraits> AutoFDClose;
+using AutoFDClose = UniquePtr<PRFileDesc, PRCloseDeleter>;
 
 /* RAII wrapper for FILE descriptors */
-struct ScopedCloseFileTraits {
-  typedef FILE* type;
-  static type empty() { return nullptr; }
-  static void release(type aFile) {
-    if (aFile) {
-      fclose(aFile);
+struct FCloseDeleter {
+  void operator()(FILE* p) {
+    if (p) {
+      fclose(p);
     }
   }
 };
-typedef Scoped<ScopedCloseFileTraits> ScopedCloseFile;
+using ScopedCloseFile = UniquePtr<FILE, FCloseDeleter>;
 
 /**
  * Fallocate efficiently and continuously allocates files via fallocate-type
diff --git a/xpcom/glue/standalone/nsXPCOMGlue.cpp b/xpcom/glue/standalone/nsXPCOMGlue.cpp
index dc0a905830c7..e8d48193e255 100644
--- a/xpcom/glue/standalone/nsXPCOMGlue.cpp
+++ b/xpcom/glue/standalone/nsXPCOMGlue.cpp
@@ -11,6 +11,7 @@
 #include <stdio.h>
 
 #include "mozilla/FileUtils.h"
+#include "mozilla/ScopeExit.h"
 #include "mozilla/Try.h"
 #include "mozilla/UniquePtr.h"
 #include "mozilla/UniquePtrExtensions.h"
@@ -166,18 +167,6 @@ inline FILE* TS_tfopen(const char* aPath, const char* aMode) {
 }
 #endif
 
-/* RAII wrapper for FILE descriptors */
-struct ScopedCloseFileTraits {
-  typedef FILE* type;
-  static type empty() { return nullptr; }
-  static void release(type aFile) {
-    if (aFile) {
-      fclose(aFile);
-    }
-  }
-};
-typedef Scoped<ScopedCloseFileTraits> ScopedCloseFile;
-
 #if !defined(MOZ_LINKER) && !defined(__ANDROID__)
 static void XPCOMGlueUnload() {
   while (sTop) {
@@ -275,8 +264,12 @@ static XPCOMGlueLoadResult XPCOMGlueLoad(
     strcat(xpcomDir, ".gtest");
   }
 
-  ScopedCloseFile flist;
-  flist = TS_tfopen(xpcomDir, READ_TEXTMODE);
+  const auto flist = TS_tfopen(xpcomDir, READ_TEXTMODE);
+  const auto cleanup = MakeScopeExit([&]() {
+    if (flist) {
+      fclose(flist);
+    }
+  });
   if (!flist) {
     return Err(AsVariant(NS_ERROR_FAILURE));
   }
diff --git a/xpcom/io/FileUtilsWin.cpp b/xpcom/io/FileUtilsWin.cpp
index 9c0bc6faa2dc..5bf7e4c968ac 100644
--- a/xpcom/io/FileUtilsWin.cpp
+++ b/xpcom/io/FileUtilsWin.cpp
@@ -11,25 +11,10 @@
 
 #include "base/process_util.h"
 #include "mozilla/ProfilerLabels.h"
+#include "mozilla/ScopeExit.h"
 #include "mozilla/Unused.h"
 #include "nsWindowsHelpers.h"
 
-namespace {
-
-// Scoped type used by HandleToFilename
-struct ScopedMappedViewTraits {
-  typedef void* type;
-  static void* empty() { return nullptr; }
-  static void release(void* aPtr) {
-    if (aPtr) {
-      mozilla::Unused << UnmapViewOfFile(aPtr);
-    }
-  }
-};
-typedef mozilla::Scoped<ScopedMappedViewTraits> ScopedMappedView;
-
-}  // namespace
-
 namespace mozilla {
 
 bool HandleToFilename(HANDLE aHandle, const LARGE_INTEGER& aOffset,
@@ -44,11 +29,14 @@ bool HandleToFilename(HANDLE aHandle, const LARGE_INTEGER& aOffset,
   if (!fileMapping) {
     return false;
   }
-  ScopedMappedView view(MapViewOfFile(fileMapping, FILE_MAP_READ,
-                                      aOffset.HighPart, aOffset.LowPart, 1));
+  const auto view = MapViewOfFile(fileMapping, FILE_MAP_READ, aOffset.HighPart,
+                                  aOffset.LowPart, 1);
   if (!view) {
     return false;
   }
+  const auto cleanup =
+      MakeScopeExit([&]() { mozilla::Unused << UnmapViewOfFile(view); });
+
   nsAutoString mappedFilename;
   DWORD len = 0;
   SetLastError(ERROR_SUCCESS);
diff --git a/xpcom/io/FileUtilsWin.h b/xpcom/io/FileUtilsWin.h
index 4a59820d083b..548aed6dd72a 100644
--- a/xpcom/io/FileUtilsWin.h
+++ b/xpcom/io/FileUtilsWin.h
@@ -9,7 +9,6 @@
 
 #include <windows.h>
 
-#include "mozilla/Scoped.h"
 #include "nsString.h"
 
 namespace mozilla {