diff --git a/dom/ipc/ContentChild.cpp b/dom/ipc/ContentChild.cpp
index dfc06abfcb6e..0d3673cd734d 100644
--- a/dom/ipc/ContentChild.cpp
+++ b/dom/ipc/ContentChild.cpp
@@ -208,11 +208,6 @@
 
 #if defined(XP_MACOSX)
 #  include "nsMacUtilsImpl.h"
-#  include <CoreServices/CoreServices.h>
-// Info.plist key associated with the developer repo path
-#  define MAC_DEV_REPO_KEY "MozillaDeveloperRepoPath"
-// Info.plist key associated with the developer repo object directory
-#  define MAC_DEV_OBJ_KEY "MozillaDeveloperObjPath"
 #endif /* XP_MACOSX */
 
 #ifdef MOZ_X11
@@ -1661,7 +1656,7 @@ static bool StartMacOSContentSandbox() {
 
   if (mozilla::IsDevelopmentBuild()) {
     nsCOMPtr<nsIFile> repoDir;
-    rv = mozilla::GetRepoDir(getter_AddRefs(repoDir));
+    rv = nsMacUtilsImpl::GetRepoDir(getter_AddRefs(repoDir));
     if (NS_FAILED(rv)) {
       MOZ_CRASH("Failed to get path to repo dir");
     }
@@ -1670,7 +1665,7 @@ static bool StartMacOSContentSandbox() {
     info.testingReadPath3.assign(repoDirPath.get());
 
     nsCOMPtr<nsIFile> objDir;
-    rv = mozilla::GetObjDir(getter_AddRefs(objDir));
+    rv = nsMacUtilsImpl::GetObjDir(getter_AddRefs(objDir));
     if (NS_FAILED(rv)) {
       MOZ_CRASH("Failed to get path to build object dir");
     }
@@ -4058,103 +4053,4 @@ bool IsDevelopmentBuild() {
 }
 #endif /* !XP_WIN */
 
-#if defined(XP_MACOSX)
-/*
- * Helper function to read a string value for a given key from the .app's
- * Info.plist.
- */
-static nsresult GetStringValueFromBundlePlist(const nsAString& aKey,
-                                              nsAutoCString& aValue) {
-  CFBundleRef mainBundle = CFBundleGetMainBundle();
-  if (mainBundle == nullptr) {
-    return NS_ERROR_FAILURE;
-  }
-
-  // Read this app's bundle Info.plist as a dictionary
-  CFDictionaryRef bundleInfoDict = CFBundleGetInfoDictionary(mainBundle);
-  if (bundleInfoDict == nullptr) {
-    return NS_ERROR_FAILURE;
-  }
-
-  nsAutoCString keyAutoCString = NS_ConvertUTF16toUTF8(aKey);
-  CFStringRef key = CFStringCreateWithCString(
-      kCFAllocatorDefault, keyAutoCString.get(), kCFStringEncodingUTF8);
-  if (key == nullptr) {
-    return NS_ERROR_FAILURE;
-  }
-
-  CFStringRef value = (CFStringRef)CFDictionaryGetValue(bundleInfoDict, key);
-  CFRelease(key);
-  if (value == nullptr) {
-    return NS_ERROR_FAILURE;
-  }
-
-  CFIndex valueLength = CFStringGetLength(value);
-  if (valueLength == 0) {
-    return NS_ERROR_FAILURE;
-  }
-
-  const char* valueCString =
-      CFStringGetCStringPtr(value, kCFStringEncodingUTF8);
-  if (valueCString) {
-    aValue.Assign(valueCString);
-    return NS_OK;
-  }
-
-  CFIndex maxLength =
-      CFStringGetMaximumSizeForEncoding(valueLength, kCFStringEncodingUTF8) + 1;
-  char* valueBuffer = static_cast<char*>(moz_xmalloc(maxLength));
-
-  if (!CFStringGetCString(value, valueBuffer, maxLength,
-                          kCFStringEncodingUTF8)) {
-    free(valueBuffer);
-    return NS_ERROR_FAILURE;
-  }
-
-  aValue.Assign(valueBuffer);
-  free(valueBuffer);
-  return NS_OK;
-}
-
-/*
- * Helper function for reading a path string from the .app's Info.plist
- * and returning a directory object for that path with symlinks resolved.
- */
-static nsresult GetDirFromBundlePlist(const nsAString& aKey, nsIFile** aDir) {
-  nsresult rv;
-
-  nsAutoCString dirPath;
-  rv = GetStringValueFromBundlePlist(aKey, dirPath);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  nsCOMPtr<nsIFile> dir;
-  rv = NS_NewLocalFile(NS_ConvertUTF8toUTF16(dirPath), false,
-                       getter_AddRefs(dir));
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  rv = dir->Normalize();
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  bool isDirectory = false;
-  rv = dir->IsDirectory(&isDirectory);
-  NS_ENSURE_SUCCESS(rv, rv);
-  if (!isDirectory) {
-    return NS_ERROR_FILE_NOT_DIRECTORY;
-  }
-
-  dir.swap(*aDir);
-  return NS_OK;
-}
-
-nsresult GetRepoDir(nsIFile** aRepoDir) {
-  MOZ_ASSERT(IsDevelopmentBuild());
-  return GetDirFromBundlePlist(NS_LITERAL_STRING(MAC_DEV_REPO_KEY), aRepoDir);
-}
-
-nsresult GetObjDir(nsIFile** aObjDir) {
-  MOZ_ASSERT(IsDevelopmentBuild());
-  return GetDirFromBundlePlist(NS_LITERAL_STRING(MAC_DEV_OBJ_KEY), aObjDir);
-}
-#endif /* XP_MACOSX */
-
 }  // namespace mozilla
diff --git a/dom/ipc/ContentChild.h b/dom/ipc/ContentChild.h
index 30d608588de5..12951b0d3b7e 100644
--- a/dom/ipc/ContentChild.h
+++ b/dom/ipc/ContentChild.h
@@ -57,14 +57,6 @@ using mozilla::loader::PScriptCacheChild;
 bool IsDevelopmentBuild();
 #endif /* !XP_WIN */
 
-#if defined(XP_MACOSX)
-// Return the repo directory and the repo object directory respectively. These
-// should only be used on Mac developer builds to determine the path to the
-// repo or object directory.
-nsresult GetRepoDir(nsIFile** aRepoDir);
-nsresult GetObjDir(nsIFile** aObjDir);
-#endif /* XP_MACOSX */
-
 namespace ipc {
 class URIParams;
 }  // namespace ipc
diff --git a/dom/ipc/ContentParent.cpp b/dom/ipc/ContentParent.cpp
index 0ae7b2898674..3a4fc7308e87 100644
--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -1989,7 +1989,7 @@ static void CacheSandboxParams(std::vector<std::string>& aCachedParams) {
   if (mozilla::IsDevelopmentBuild()) {
     // Repo dir
     nsCOMPtr<nsIFile> repoDir;
-    rv = mozilla::GetRepoDir(getter_AddRefs(repoDir));
+    rv = nsMacUtilsImpl::GetRepoDir(getter_AddRefs(repoDir));
     if (NS_FAILED(rv)) {
       MOZ_CRASH("Failed to get path to repo dir");
     }
@@ -1999,7 +1999,7 @@ static void CacheSandboxParams(std::vector<std::string>& aCachedParams) {
 
     // Object dir
     nsCOMPtr<nsIFile> objDir;
-    rv = mozilla::GetObjDir(getter_AddRefs(objDir));
+    rv = nsMacUtilsImpl::GetObjDir(getter_AddRefs(objDir));
     if (NS_FAILED(rv)) {
       MOZ_CRASH("Failed to get path to build object dir");
     }
diff --git a/netwerk/protocol/res/ExtensionProtocolHandler.cpp b/netwerk/protocol/res/ExtensionProtocolHandler.cpp
index 2538cdbddd21..fb96bf4b1755 100644
--- a/netwerk/protocol/res/ExtensionProtocolHandler.cpp
+++ b/netwerk/protocol/res/ExtensionProtocolHandler.cpp
@@ -52,6 +52,10 @@
 #  include "WinUtils.h"
 #endif
 
+#if defined(XP_MACOSX)
+#  include "nsMacUtilsImpl.h"
+#endif
+
 #define EXTENSION_SCHEME "moz-extension"
 using mozilla::dom::Promise;
 using mozilla::ipc::FileDescriptor;
@@ -612,7 +616,7 @@ Result<bool, nsresult> ExtensionProtocolHandler::DevRepoContains(
   // On the first invocation, set mDevRepo
   if (!mAlreadyCheckedDevRepo) {
     mAlreadyCheckedDevRepo = true;
-    MOZ_TRY(mozilla::GetRepoDir(getter_AddRefs(mDevRepo)));
+    MOZ_TRY(nsMacUtilsImpl::GetRepoDir(getter_AddRefs(mDevRepo)));
     if (MOZ_LOG_TEST(gExtProtocolLog, LogLevel::Debug)) {
       nsAutoCString repoPath;
       Unused << mDevRepo->GetNativePath(repoPath);
diff --git a/netwerk/protocol/res/moz.build b/netwerk/protocol/res/moz.build
index ec6a57069896..d6791156da8d 100644
--- a/netwerk/protocol/res/moz.build
+++ b/netwerk/protocol/res/moz.build
@@ -35,4 +35,5 @@ FINAL_LIBRARY = 'xul'
 
 LOCAL_INCLUDES += [
     '/netwerk/base',
+    '/xpcom/base',
 ]
diff --git a/xpcom/base/nsMacUtilsImpl.cpp b/xpcom/base/nsMacUtilsImpl.cpp
index 5aad7864b070..ecec6733ac75 100644
--- a/xpcom/base/nsMacUtilsImpl.cpp
+++ b/xpcom/base/nsMacUtilsImpl.cpp
@@ -8,6 +8,7 @@
 
 #include "base/command_line.h"
 #include "mozilla/ClearOnShutdown.h"
+#include "mozilla/dom/ContentChild.h"
 #include "nsDirectoryServiceDefs.h"
 #include "nsCOMPtr.h"
 #include "nsIFile.h"
@@ -16,7 +17,12 @@
 #include "nsXULAppAPI.h"
 #include "prenv.h"
 
+#if defined(MOZ_SANDBOX)
+#include "mozilla/SandboxSettings.h"
+#endif
+
 #include <CoreFoundation/CoreFoundation.h>
+#include <CoreServices/CoreServices.h>
 #include <sys/sysctl.h>
 
 NS_IMPL_ISUPPORTS(nsMacUtilsImpl, nsIMacUtils)
@@ -29,6 +35,11 @@ StaticAutoPtr<nsCString> nsMacUtilsImpl::sCachedAppPath;
 StaticMutex nsMacUtilsImpl::sCachedAppPathMutex;
 #endif
 
+// Info.plist key associated with the developer repo path
+#define MAC_DEV_REPO_KEY "MozillaDeveloperRepoPath"
+// Info.plist key associated with the developer repo object directory
+#define MAC_DEV_OBJ_KEY "MozillaDeveloperObjPath"
+
 // Initialize with Unknown until we've checked if TCSM is available to set
 Atomic<nsMacUtilsImpl::TCSMStatus> nsMacUtilsImpl::sTCSMStatus(TCSM_Unknown);
 
@@ -207,6 +218,92 @@ bool nsMacUtilsImpl::GetAppPath(nsCString& aAppPath) {
   return true;
 }
 
+/*
+ * Helper function to read a string value for a given key from the .app's
+ * Info.plist.
+ */
+static nsresult GetStringValueFromBundlePlist(const nsAString& aKey,
+                                              nsAutoCString& aValue) {
+  CFBundleRef mainBundle = CFBundleGetMainBundle();
+  if (mainBundle == nullptr) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Read this app's bundle Info.plist as a dictionary
+  CFDictionaryRef bundleInfoDict = CFBundleGetInfoDictionary(mainBundle);
+  if (bundleInfoDict == nullptr) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsAutoCString keyAutoCString = NS_ConvertUTF16toUTF8(aKey);
+  CFStringRef key = CFStringCreateWithCString(
+      kCFAllocatorDefault, keyAutoCString.get(), kCFStringEncodingUTF8);
+  if (key == nullptr) {
+    return NS_ERROR_FAILURE;
+  }
+
+  CFStringRef value = (CFStringRef)CFDictionaryGetValue(bundleInfoDict, key);
+  CFRelease(key);
+  if (value == nullptr) {
+    return NS_ERROR_FAILURE;
+  }
+
+  CFIndex valueLength = CFStringGetLength(value);
+  if (valueLength == 0) {
+    return NS_ERROR_FAILURE;
+  }
+
+  const char* valueCString =
+      CFStringGetCStringPtr(value, kCFStringEncodingUTF8);
+  if (valueCString) {
+    aValue.Assign(valueCString);
+    return NS_OK;
+  }
+
+  CFIndex maxLength =
+      CFStringGetMaximumSizeForEncoding(valueLength, kCFStringEncodingUTF8) + 1;
+  char* valueBuffer = static_cast<char*>(moz_xmalloc(maxLength));
+
+  if (!CFStringGetCString(value, valueBuffer, maxLength,
+                          kCFStringEncodingUTF8)) {
+    free(valueBuffer);
+    return NS_ERROR_FAILURE;
+  }
+
+  aValue.Assign(valueBuffer);
+  free(valueBuffer);
+  return NS_OK;
+}
+/*
+ * Helper function for reading a path string from the .app's Info.plist
+ * and returning a directory object for that path with symlinks resolved.
+ */
+static nsresult GetDirFromBundlePlist(const nsAString& aKey, nsIFile** aDir) {
+  nsresult rv;
+
+  nsAutoCString dirPath;
+  rv = GetStringValueFromBundlePlist(aKey, dirPath);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIFile> dir;
+  rv = NS_NewLocalFile(NS_ConvertUTF8toUTF16(dirPath), false,
+                       getter_AddRefs(dir));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = dir->Normalize();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool isDirectory = false;
+  rv = dir->IsDirectory(&isDirectory);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!isDirectory) {
+    return NS_ERROR_FILE_NOT_DIRECTORY;
+  }
+
+  dir.swap(*aDir);
+  return NS_OK;
+}
+
 #  if defined(DEBUG)
 // If XPCOM_MEM_BLOAT_LOG or XPCOM_MEM_LEAK_LOG is set to a log file
 // path, return the path to the parent directory (where sibling log
@@ -315,3 +412,105 @@ uint32_t nsMacUtilsImpl::GetPhysicalCPUCount() {
   }
   return oldVal;
 }
+
+/*
+ * Helper function to read a string value for a given key from the .app's
+ * Info.plist.
+ */
+static nsresult GetStringValueFromBundlePlist(const nsAString& aKey,
+                                              nsAutoCString& aValue) {
+  CFBundleRef mainBundle = CFBundleGetMainBundle();
+  if (mainBundle == nullptr) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Read this app's bundle Info.plist as a dictionary
+  CFDictionaryRef bundleInfoDict = CFBundleGetInfoDictionary(mainBundle);
+  if (bundleInfoDict == nullptr) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsAutoCString keyAutoCString = NS_ConvertUTF16toUTF8(aKey);
+  CFStringRef key = CFStringCreateWithCString(
+      kCFAllocatorDefault, keyAutoCString.get(), kCFStringEncodingUTF8);
+  if (key == nullptr) {
+    return NS_ERROR_FAILURE;
+  }
+
+  CFStringRef value = (CFStringRef)CFDictionaryGetValue(bundleInfoDict, key);
+  CFRelease(key);
+  if (value == nullptr) {
+    return NS_ERROR_FAILURE;
+  }
+
+  CFIndex valueLength = CFStringGetLength(value);
+  if (valueLength == 0) {
+    return NS_ERROR_FAILURE;
+  }
+
+  const char* valueCString =
+      CFStringGetCStringPtr(value, kCFStringEncodingUTF8);
+  if (valueCString) {
+    aValue.Assign(valueCString);
+    return NS_OK;
+  }
+
+  CFIndex maxLength =
+      CFStringGetMaximumSizeForEncoding(valueLength, kCFStringEncodingUTF8) + 1;
+  char* valueBuffer = static_cast<char*>(moz_xmalloc(maxLength));
+
+  if (!CFStringGetCString(value, valueBuffer, maxLength,
+                          kCFStringEncodingUTF8)) {
+    free(valueBuffer);
+    return NS_ERROR_FAILURE;
+  }
+
+  aValue.Assign(valueBuffer);
+  free(valueBuffer);
+  return NS_OK;
+}
+
+/*
+ * Helper function for reading a path string from the .app's Info.plist
+ * and returning a directory object for that path with symlinks resolved.
+ */
+static nsresult GetDirFromBundlePlist(const nsAString& aKey, nsIFile** aDir) {
+  nsresult rv;
+
+  nsAutoCString dirPath;
+  rv = GetStringValueFromBundlePlist(aKey, dirPath);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIFile> dir;
+  rv = NS_NewLocalFile(NS_ConvertUTF8toUTF16(dirPath), false,
+                       getter_AddRefs(dir));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = dir->Normalize();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  bool isDirectory = false;
+  rv = dir->IsDirectory(&isDirectory);
+  NS_ENSURE_SUCCESS(rv, rv);
+  if (!isDirectory) {
+    return NS_ERROR_FILE_NOT_DIRECTORY;
+  }
+
+  dir.swap(*aDir);
+  return NS_OK;
+}
+
+nsresult nsMacUtilsImpl::GetRepoDir(nsIFile** aRepoDir) {
+#if defined(MOZ_SANDBOX)
+  MOZ_ASSERT(mozilla::IsDevelopmentBuild());
+#endif
+  return GetDirFromBundlePlist(NS_LITERAL_STRING(MAC_DEV_REPO_KEY), aRepoDir);
+}
+
+nsresult nsMacUtilsImpl::GetObjDir(nsIFile** aObjDir) {
+#if defined(MOZ_SANDBOX)
+  MOZ_ASSERT(mozilla::IsDevelopmentBuild());
+#endif
+  return GetDirFromBundlePlist(NS_LITERAL_STRING(MAC_DEV_OBJ_KEY), aObjDir);
+}
+
diff --git a/xpcom/base/nsMacUtilsImpl.h b/xpcom/base/nsMacUtilsImpl.h
index cdbd4aad3758..1fc9254bb9c3 100644
--- a/xpcom/base/nsMacUtilsImpl.h
+++ b/xpcom/base/nsMacUtilsImpl.h
@@ -25,9 +25,14 @@ class nsMacUtilsImpl final : public nsIMacUtils {
 
   nsMacUtilsImpl() {}
 
+  // Return the repo directory and the repo object directory respectively.
+  // These should only be used on Mac developer builds to determine the path
+  // to the repo or object directory.
+  static nsresult GetRepoDir(nsIFile** aRepoDir);
+  static nsresult GetObjDir(nsIFile** aObjDir);
+
 #if defined(MOZ_SANDBOX)
   static bool GetAppPath(nsCString& aAppPath);
-
 #  ifdef DEBUG
   static nsresult GetBloatLogDir(nsCString& aDirectoryPath);
   static nsresult GetDirectoryPath(const char* aPath,