--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoAppShell.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoAppShell.java
@@ -1056,26 +1056,16 @@ public class GeckoAppShell
     @WrapForJNI(calledFrom = "gecko")
     private static void cancelVibrate() {
         sVibrationMaybePlaying = false;
         sVibrationEndTime = 0;
         vibrator().cancel();
     }
 
     @WrapForJNI(calledFrom = "gecko")
-    private static void setKeepScreenOn(final boolean on) {
-        ThreadUtils.postToUiThread(new Runnable() {
-            @Override
-            public void run() {
-                // TODO
-            }
-        });
-    }
-
-    @WrapForJNI(calledFrom = "gecko")
     private static boolean isNetworkLinkUp() {
         ConnectivityManager cm = (ConnectivityManager)
            getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);
         try {
             NetworkInfo info = cm.getActiveNetworkInfo();
             if (info == null || !info.isConnected())
                 return false;
         } catch (SecurityException se) {

--- a/widget/android/GeneratedJNIWrappers.cpp
+++ b/widget/android/GeneratedJNIWrappers.cpp
@@ -601,24 +601,16 @@ auto GeckoAppShell::ScheduleRestart() ->
 constexpr char GeckoAppShell::SetFullScreen_t::name[];
 constexpr char GeckoAppShell::SetFullScreen_t::signature[];
 
 auto GeckoAppShell::SetFullScreen(bool a0) -> void
 {
     return mozilla::jni::Method<SetFullScreen_t>::Call(GeckoAppShell::Context(), nullptr, a0);
 }
 
-constexpr char GeckoAppShell::SetKeepScreenOn_t::name[];
-constexpr char GeckoAppShell::SetKeepScreenOn_t::signature[];
-
-auto GeckoAppShell::SetKeepScreenOn(bool a0) -> void
-{
-    return mozilla::jni::Method<SetKeepScreenOn_t>::Call(GeckoAppShell::Context(), nullptr, a0);
-}
-
 constexpr char GeckoAppShell::SetScreenDepthOverride_t::name[];
 constexpr char GeckoAppShell::SetScreenDepthOverride_t::signature[];
 
 auto GeckoAppShell::SetScreenDepthOverride(int32_t a0) -> void
 {
     return mozilla::jni::Method<SetScreenDepthOverride_t>::Call(GeckoAppShell::Context(), nullptr, a0);
 }
 

--- a/widget/android/GeneratedJNIWrappers.h
+++ b/widget/android/GeneratedJNIWrappers.h
@@ -1697,36 +1697,16 @@ public:
         static const mozilla::jni::CallingThread callingThread =
                 mozilla::jni::CallingThread::GECKO;
         static const mozilla::jni::DispatchTarget dispatchTarget =
                 mozilla::jni::DispatchTarget::CURRENT;
     };
 
     static auto SetFullScreen(bool) -> void;
 
-    struct SetKeepScreenOn_t {
-        typedef GeckoAppShell Owner;
-        typedef void ReturnType;
-        typedef void SetterType;
-        typedef mozilla::jni::Args<
-                bool> Args;
-        static constexpr char name[] = "setKeepScreenOn";
-        static constexpr char signature[] =
-                "(Z)V";
-        static const bool isStatic = true;
-        static const mozilla::jni::ExceptionMode exceptionMode =
-                mozilla::jni::ExceptionMode::ABORT;
-        static const mozilla::jni::CallingThread callingThread =
-                mozilla::jni::CallingThread::GECKO;
-        static const mozilla::jni::DispatchTarget dispatchTarget =
-                mozilla::jni::DispatchTarget::CURRENT;
-    };
-
-    static auto SetKeepScreenOn(bool) -> void;
-
     struct SetScreenDepthOverride_t {
         typedef GeckoAppShell Owner;
         typedef void ReturnType;
         typedef void SetterType;
         typedef mozilla::jni::Args<
                 int32_t> Args;
         static constexpr char name[] = "setScreenDepthOverride";
         static constexpr char signature[] =

--- a/widget/android/nsScreenManagerAndroid.cpp
+++ b/widget/android/nsScreenManagerAndroid.cpp
@@ -112,26 +112,16 @@ nsScreenAndroid::GetPixelDepth(int32_t *
 
 
 NS_IMETHODIMP
 nsScreenAndroid::GetColorDepth(int32_t *aColorDepth)
 {
     return GetPixelDepth(aColorDepth);
 }
 
-
-void
-nsScreenAndroid::ApplyMinimumBrightness(uint32_t aBrightness)
-{
-    if (mDisplayType == DisplayType::DISPLAY_PRIMARY &&
-        mozilla::jni::IsAvailable()) {
-        java::GeckoAppShell::SetKeepScreenOn(aBrightness == BRIGHTNESS_FULL);
-    }
-}
-
 class nsScreenManagerAndroid::ScreenManagerHelperSupport final
     : public ScreenManagerHelper::Natives<ScreenManagerHelperSupport>
 {
 public:
     typedef ScreenManagerHelper::Natives<ScreenManagerHelperSupport> Base;
 
     static int32_t AddDisplay(int32_t aDisplayType, int32_t aWidth, int32_t aHeight, float aDensity) {
         int32_t screenId = -1; // return value

--- a/widget/android/nsScreenManagerAndroid.h
+++ b/widget/android/nsScreenManagerAndroid.h
@@ -27,19 +27,16 @@ public:
     NS_IMETHOD GetColorDepth(int32_t* aColorDepth) override;
 
     uint32_t GetId() const { return mId; };
     DisplayType GetDisplayType() const { return mDisplayType; }
 
     void SetDensity(double aDensity) { mDensity = aDensity; }
     float GetDensity();
 
-protected:
-    virtual void ApplyMinimumBrightness(uint32_t aBrightness) override;
-
 private:
     uint32_t mId;
     DisplayType mDisplayType;
     nsIntRect mRect;
     float mDensity;
 };
 
 class nsScreenManagerAndroid final : public nsIScreenManager

--- a/widget/nsBaseScreen.cpp
+++ b/widget/nsBaseScreen.cpp
@@ -8,18 +8,16 @@
 #define MOZ_FATAL_ASSERTIONS_FOR_THREAD_SAFETY
 
 #include "nsBaseScreen.h"
 
 NS_IMPL_ISUPPORTS(nsBaseScreen, nsIScreen)
 
 nsBaseScreen::nsBaseScreen()
 {
-  for (uint32_t i = 0; i < nsIScreen::BRIGHTNESS_LEVELS; i++)
-    mBrightnessLocks[i] = 0;
 }
 
 nsBaseScreen::~nsBaseScreen() { }
 
 NS_IMETHODIMP
 nsBaseScreen::GetRectDisplayPix(int32_t *outLeft,  int32_t *outTop,
                                 int32_t *outWidth, int32_t *outHeight)
 {
@@ -29,58 +27,16 @@ nsBaseScreen::GetRectDisplayPix(int32_t 
 NS_IMETHODIMP
 nsBaseScreen::GetAvailRectDisplayPix(int32_t *outLeft,  int32_t *outTop,
                                      int32_t *outWidth, int32_t *outHeight)
 {
   return GetAvailRect(outLeft, outTop, outWidth, outHeight);
 }
 
 NS_IMETHODIMP
-nsBaseScreen::LockMinimumBrightness(uint32_t aBrightness)
-{
-  MOZ_ASSERT(aBrightness < nsIScreen::BRIGHTNESS_LEVELS,
-             "Invalid brightness level to lock");
-  mBrightnessLocks[aBrightness]++;
-  MOZ_ASSERT(mBrightnessLocks[aBrightness] > 0,
-             "Overflow after locking brightness level");
-
-  CheckMinimumBrightness();
-
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsBaseScreen::UnlockMinimumBrightness(uint32_t aBrightness)
-{
-  MOZ_ASSERT(aBrightness < nsIScreen::BRIGHTNESS_LEVELS,
-             "Invalid brightness level to lock");
-  MOZ_ASSERT(mBrightnessLocks[aBrightness] > 0,
-             "Unlocking a brightness level with no corresponding lock");
-  mBrightnessLocks[aBrightness]--;
-
-  CheckMinimumBrightness();
-
-  return NS_OK;
-}
-
-void
-nsBaseScreen::CheckMinimumBrightness()
-{
-  uint32_t brightness = nsIScreen::BRIGHTNESS_LEVELS;
-  for (int32_t i = nsIScreen::BRIGHTNESS_LEVELS - 1; i >=0; i--) {
-    if (mBrightnessLocks[i] > 0) {
-      brightness = i;
-      break;
-    }
-  }
-
-  ApplyMinimumBrightness(brightness);
-}
-
-NS_IMETHODIMP
 nsBaseScreen::GetContentsScaleFactor(double* aContentsScaleFactor)
 {
   *aContentsScaleFactor = 1.0;
   return NS_OK;
 }
 
 NS_IMETHODIMP
 nsBaseScreen::GetDefaultCSSScaleFactor(double* aScaleFactor)

--- a/widget/nsBaseScreen.h
+++ b/widget/nsBaseScreen.h
@@ -23,59 +23,23 @@ public:
   // These simply forward to the device-pixel versions;
   // implementations where desktop pixels may not correspond
   // to per-screen device pixels must override.
   NS_IMETHOD GetRectDisplayPix(int32_t *outLeft,  int32_t *outTop,
                                int32_t *outWidth, int32_t *outHeight) override;
   NS_IMETHOD GetAvailRectDisplayPix(int32_t *outLeft,  int32_t *outTop,
                                     int32_t *outWidth, int32_t *outHeight) override;
 
-  /**
-   * Simple management of screen brightness locks. This abstract base class
-   * allows all widget implementations to share brightness locking code.
-   */
-  NS_IMETHOD LockMinimumBrightness(uint32_t aBrightness) override;
-  NS_IMETHOD UnlockMinimumBrightness(uint32_t aBrightness) override;
-
   NS_IMETHOD GetRotation(uint32_t* aRotation) override {
     *aRotation = nsIScreen::ROTATION_0_DEG;
     return NS_OK;
   }
   NS_IMETHOD SetRotation(uint32_t aRotation) override { return NS_ERROR_NOT_AVAILABLE; }
 
   NS_IMETHOD GetContentsScaleFactor(double* aContentsScaleFactor) override;
 
   NS_IMETHOD GetDefaultCSSScaleFactor(double* aScaleFactor) override;
 
 protected:
   virtual ~nsBaseScreen();
-
-  /**
-   * Manually set the current level of brightness locking. This is called after
-   * we determine, based on the current active locks, what the strongest
-   * lock is. You should normally not call this function - it will be
-   * called automatically by this class.
-   *
-   * Each widget implementation should implement this in a way that
-   * makes sense there. This is normally the only function that
-   * contains widget-specific code.
-   *
-   * The default implementation does nothing.
-   *
-   * @param aBrightness The current brightness level to set. If this is
-   *                    nsIScreen::BRIGHTNESS_LEVELS
-   *                    (an impossible value for a brightness level to be),
-   *                    then that signifies that there is no current
-   *                    minimum brightness level, and the screen can shut off.
-   */
-  virtual void ApplyMinimumBrightness(uint32_t aBrightness) { }
-
-private:
-  /**
-   * Checks what the minimum brightness value is, and calls
-   * ApplyMinimumBrightness.
-   */
-  void CheckMinimumBrightness();
-
-  uint32_t mBrightnessLocks[nsIScreen::BRIGHTNESS_LEVELS];
 };
 
 #endif // nsBaseScreen_h

--- a/widget/nsIScreen.idl
+++ b/widget/nsIScreen.idl
@@ -16,25 +16,16 @@ enum class DisplayType: int32_t {
   DISPLAY_VIRTUAL   // wireless displays, such as Chromecast, WiFi-Display, etc.
 };
 %}
 
 [scriptable, uuid(826e80c8-d70f-42e2-8aa9-82c05f2a370a)]
 interface nsIScreen : nsISupports
 {
   /**
-   * Levels of brightness for the screen, from off to full brightness.
-   */
-  const unsigned long BRIGHTNESS_DIM = 0;
-  const unsigned long BRIGHTNESS_FULL = 1;
-
-  /* The number of different brightness levels */
-  const unsigned long BRIGHTNESS_LEVELS = 2;
-
-  /**
    * Allowable screen rotations, when the underlying widget toolkit
    * supports rotating the screen.
    *
    * ROTATION_0_DEG is the default, unrotated configuration.
    */
   const unsigned long   ROTATION_0_DEG = 0;
   const unsigned long  ROTATION_90_DEG = 1;
   const unsigned long ROTATION_180_DEG = 2;
@@ -53,34 +44,16 @@ interface nsIScreen : nsISupports
   void GetAvailRect(out long left, out long top, out long width, out long height);
 
   /**
    * And these report in desktop pixels
    */
   void GetRectDisplayPix(out long left, out long top, out long width, out long height);
   void GetAvailRectDisplayPix(out long left, out long top, out long width, out long height);
 
-  /**
-   * Locks the minimum brightness of the screen, forcing it to be at
-   * least as bright as a certain brightness level. Each call to this
-   * function must eventually be followed by a corresponding call to
-   * unlockMinimumBrightness, with the same brightness level.
-   *
-   * @param brightness A brightness level, one of the above constants.
-   */
-  void lockMinimumBrightness(in unsigned long brightness);
-
-  /**
-   * Releases a lock on the screen brightness. This must be called
-   * (eventually) after a corresponding call to lockMinimumBrightness.
-   *
-   * @param brightness A brightness level, one of the above constants.
-   */
-  void unlockMinimumBrightness(in unsigned long brightness);
-  
   readonly attribute long pixelDepth;
   readonly attribute long colorDepth;
   /**
    * Get/set the screen rotation, on platforms that support changing
    * screen rotation.
    */
   attribute unsigned long rotation;