diff --git a/dom/media/MediaManager.cpp b/dom/media/MediaManager.cpp
index b195726a6396..48d503493693 100644
--- a/dom/media/MediaManager.cpp
+++ b/dom/media/MediaManager.cpp
@@ -18,6 +18,8 @@
 #include "nsDOMFile.h"
 #include "nsGlobalWindow.h"
 
+#include "mozilla/Preferences.h"
+
 /* Using WebRTC backend on Desktops (Mac, Windows, Linux), otherwise default */
 #include "MediaEngineDefault.h"
 #if defined(MOZ_WEBRTC)
@@ -673,6 +675,11 @@ MediaManager::GetUserMedia(bool aPrivileged, nsPIDOMWindow* aWindow,
     mActiveWindows.Put(windowID, listeners);
   }
 
+  // Developer preference for turning off permission check.
+  if (Preferences::GetBool("media.navigator.permission.disabled", false)) {
+    aPrivileged = true;
+  }
+
   /**
    * Pass runnables along to GetUserMediaRunnable so it can add the
    * MediaStreamListener to the runnable list. The last argument can
@@ -706,7 +713,7 @@ MediaManager::GetUserMedia(bool aPrivileged, nsPIDOMWindow* aWindow,
   if (picture) {
     // ShowFilePickerForMimeType() must run on the Main Thread! (on Android)
     NS_DispatchToMainThread(gUMRunnable);
-  } else if (aPrivileged) {
+  } else if (aPrivileged || fake) {
     if (!mMediaThread) {
       nsresult rv = NS_NewThread(getter_AddRefs(mMediaThread));
       NS_ENSURE_SUCCESS(rv, rv);
diff --git a/modules/libpref/src/init/all.js b/modules/libpref/src/init/all.js
index f8a18213e52b..387259287c3e 100644
--- a/modules/libpref/src/init/all.js
+++ b/modules/libpref/src/init/all.js
@@ -174,6 +174,7 @@ pref("media.h264.enabled", true);
 #ifdef MOZ_WEBRTC
 pref("media.navigator.enabled", false);
 pref("media.peerconnection.enabled", false);
+pref("media.navigator.permission.disabled", false);
 #else
 #ifdef ANDROID
 pref("media.navigator.enabled", true);