diff --git a/browser/base/content/test/webrtc/head.js b/browser/base/content/test/webrtc/head.js
index c033152f637d..c02174dbb835 100644
--- a/browser/base/content/test/webrtc/head.js
+++ b/browser/base/content/test/webrtc/head.js
@@ -5,6 +5,7 @@ const PREF_PERMISSION_FAKE = "media.navigator.permission.fake";
 const PREF_AUDIO_LOOPBACK = "media.audio_loopback_dev";
 const PREF_VIDEO_LOOPBACK = "media.video_loopback_dev";
 const PREF_FAKE_STREAMS = "media.navigator.streams.fake";
+const PREF_FOCUS_SOURCE = "media.getusermedia.window.focus_source.enabled";
 const CONTENT_SCRIPT_HELPER = getRootDirectory(gTestPath) + "get_user_media_content_script.js";
 
 const STATE_CAPTURE_ENABLED = Ci.nsIMediaManagerService.STATE_CAPTURE_ENABLED;
@@ -574,7 +575,8 @@ async function runTests(tests, options = {}) {
     [PREF_PERMISSION_FAKE, true],
     [PREF_AUDIO_LOOPBACK, ""],
     [PREF_VIDEO_LOOPBACK, ""],
-    [PREF_FAKE_STREAMS, true]
+    [PREF_FAKE_STREAMS, true],
+    [PREF_FOCUS_SOURCE, false]
   ];
   await SpecialPowers.pushPrefEnv({"set": prefs});
 
diff --git a/dom/media/MediaManager.cpp b/dom/media/MediaManager.cpp
index 681f47d99c04..ab7fd9900266 100644
--- a/dom/media/MediaManager.cpp
+++ b/dom/media/MediaManager.cpp
@@ -1636,7 +1636,8 @@ public:
     MediaEnginePrefs& aPrefs,
     const ipc::PrincipalInfo& aPrincipalInfo,
     bool aIsChrome,
-    MediaManager::SourceSet* aSourceSet)
+    MediaManager::SourceSet* aSourceSet,
+    bool aShouldFocusSource)
     : Runnable("GetUserMediaTask")
     , mConstraints(aConstraints)
     , mOnSuccess(aOnSuccess)
@@ -1647,6 +1648,7 @@ public:
     , mPrefs(aPrefs)
     , mPrincipalInfo(aPrincipalInfo)
     , mIsChrome(aIsChrome)
+    , mShouldFocusSource(aShouldFocusSource)
     , mDeviceChosen(false)
     , mSourceSet(aSourceSet)
     , mManager(MediaManager::GetInstance())
@@ -1719,9 +1721,12 @@ public:
         }
       } else {
         if (!mIsChrome) {
-          rv = mVideoDevice->FocusOnSelectedSource();
-          if (NS_FAILED(rv)) {
-            LOG(("FocusOnSelectedSource failed"));
+          if (mShouldFocusSource) {
+            rv = mVideoDevice->FocusOnSelectedSource();
+
+            if (NS_FAILED(rv)) {
+              LOG(("FocusOnSelectedSource failed"));
+            }
           }
         }
       }
@@ -1833,6 +1838,7 @@ private:
   MediaEnginePrefs mPrefs;
   ipc::PrincipalInfo mPrincipalInfo;
   bool mIsChrome;
+  bool mShouldFocusSource;
 
   bool mDeviceChosen;
 public:
@@ -2889,6 +2895,9 @@ MediaManager::GetUserMedia(nsPIDOMWindowInner* aWindow,
         }
       }
 
+      bool focusSource;
+      focusSource = mozilla::Preferences::GetBool("media.getusermedia.window.focus_source.enabled", true);
+
       // Pass callbacks and listeners along to GetUserMediaTask.
       RefPtr<GetUserMediaTask> task (new GetUserMediaTask(c,
                                                           onSuccess,
@@ -2899,7 +2908,8 @@ MediaManager::GetUserMedia(nsPIDOMWindowInner* aWindow,
                                                           prefs,
                                                           principalInfo,
                                                           isChrome,
-                                                          devices->release()));
+                                                          devices->release(),
+                                                          focusSource));
       // Store the task w/callbacks.
       self->mActiveCallbacks.Put(callID, task.forget());
 
diff --git a/dom/media/tests/mochitest/head.js b/dom/media/tests/mochitest/head.js
index 8798795f2d0d..6fd80abba209 100644
--- a/dom/media/tests/mochitest/head.js
+++ b/dom/media/tests/mochitest/head.js
@@ -418,8 +418,9 @@ function setupEnvironment() {
       // If either fake audio or video is desired we enable fake streams.
       // If loopback devices are set they will be chosen instead of fakes in gecko.
       ['media.navigator.streams.fake', WANT_FAKE_AUDIO || WANT_FAKE_VIDEO],
-      ['media.getusermedia.screensharing.enabled', true],
       ['media.getusermedia.audiocapture.enabled', true],
+      ['media.getusermedia.screensharing.enabled', true],
+      ['media.getusermedia.window.focus_source.enabled', false],
       ['media.recorder.audio_node.enabled', true],
       ['media.webaudio.audiocontextoptions-samplerate.enabled', true]
     ]