--- a/mobile/android/base/java/org/mozilla/gecko/GeckoApp.java
+++ b/mobile/android/base/java/org/mozilla/gecko/GeckoApp.java
@@ -2,16 +2,17 @@
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 package org.mozilla.gecko;
 
 import org.mozilla.gecko.AppConstants.Versions;
 import org.mozilla.gecko.GeckoProfileDirectories.NoMozillaDirectoryException;
+import org.mozilla.gecko.GeckoScreenOrientation.ScreenOrientation;
 import org.mozilla.gecko.annotation.RobocopTarget;
 import org.mozilla.gecko.annotation.WrapForJNI;
 import org.mozilla.gecko.health.HealthRecorder;
 import org.mozilla.gecko.health.SessionInformation;
 import org.mozilla.gecko.health.StubbedHealthRecorder;
 import org.mozilla.gecko.home.HomeConfig.PanelType;
 import org.mozilla.gecko.menu.GeckoMenu;
 import org.mozilla.gecko.menu.GeckoMenuInflater;
@@ -107,16 +108,17 @@ import static org.mozilla.gecko.Tabs.INV
 import static org.mozilla.gecko.mma.MmaDelegate.DOWNLOAD_MEDIA_SAVED_IMAGE;
 import static org.mozilla.gecko.mma.MmaDelegate.READER_AVAILABLE;
 
 public abstract class GeckoApp extends GeckoActivity
                                implements AnchoredPopup.OnVisibilityChangeListener,
                                           BundleEventListener,
                                           GeckoMenu.Callback,
                                           GeckoMenu.MenuPresenter,
+                                          GeckoScreenOrientation.OrientationChangeListener,
                                           GeckoSession.ContentDelegate,
                                           ScreenOrientationDelegate,
                                           Tabs.OnTabsChangedListener,
                                           ViewTreeObserver.OnGlobalLayoutListener {
 
     private static final String LOGTAG = "GeckoApp";
     private static final long ONE_DAY_MS = TimeUnit.MILLISECONDS.convert(1, TimeUnit.DAYS);
 
@@ -976,16 +978,17 @@ public abstract class GeckoApp extends G
         earlyStartJavaSampler(intent);
 
         // Workaround for <http://code.google.com/p/android/issues/detail?id=20915>.
         try {
             Class.forName("android.os.AsyncTask");
         } catch (ClassNotFoundException e) { }
 
         GeckoAppShell.setScreenOrientationDelegate(this);
+        GeckoScreenOrientation.getInstance().addListener(this);
 
         // Tell Stumbler to register a local broadcast listener to listen for preference intents.
         // We do this via intents since we can't easily access Stumbler directly,
         // as it might be compiled outside of Fennec.
         final Intent stumblerIntent = new Intent(getApplicationContext(), SafeReceiver.class);
         stumblerIntent.setAction(INTENT_REGISTER_STUMBLER_LISTENER);
         getApplicationContext().sendBroadcast(stumblerIntent);
 
@@ -1924,21 +1927,16 @@ public abstract class GeckoApp extends G
         if (mIsAbortingAppLaunch) {
             return;
         }
 
         foregrounded = true;
 
         GeckoAppShell.setScreenOrientationDelegate(this);
 
-        int newOrientation = getResources().getConfiguration().orientation;
-        if (GeckoScreenOrientation.getInstance().update(newOrientation)) {
-            refreshChrome();
-        }
-
         // We use two times: a pseudo-unique wall-clock time to identify the
         // current session across power cycles, and the elapsed realtime to
         // track the duration of the session.
         final long now = System.currentTimeMillis();
         final long realTime = android.os.SystemClock.elapsedRealtime();
 
         ThreadUtils.postToBackgroundThread(new Runnable() {
             @Override
@@ -2128,16 +2126,18 @@ public abstract class GeckoApp extends G
             });
         }
 
         super.onDestroy();
 
         Tabs.unregisterOnTabsChangedListener(this);
         Tabs.getInstance().detachFromContext();
 
+        GeckoScreenOrientation.getInstance().removeListener(this);
+
         if (mShutdownOnDestroy) {
             GeckoApplication.shutdown(!mRestartOnShutdown ? null : new Intent(
                     Intent.ACTION_MAIN, /* uri */ null, getApplicationContext(), getClass()));
         }
     }
 
     public void showSDKVersionError() {
         final String message = getString(R.string.unsupported_sdk_version,
@@ -2175,21 +2175,17 @@ public abstract class GeckoApp extends G
         final Locale changed = localeManager.onSystemConfigurationChanged(this, getResources(), newConfig, mLastLocale);
         if (changed != null) {
             onLocaleChanged(Locales.getLanguageTag(changed));
         }
 
         // onConfigurationChanged is not called for 180 degree orientation changes,
         // we will miss such rotations and the screen orientation will not be
         // updated.
-        if (GeckoScreenOrientation.getInstance().update(newConfig.orientation)) {
-            if (mFormAssistPopup != null)
-                mFormAssistPopup.hide();
-            refreshChrome();
-        }
+        GeckoScreenOrientation.getInstance().update(newConfig.orientation);
 
         if (mPromptService != null) {
             mPromptService.changePromptOrientation(newConfig.orientation);
         }
 
         super.onConfigurationChanged(newConfig);
     }
 
@@ -2522,9 +2518,17 @@ public abstract class GeckoApp extends G
         // We want to support the Screen Orientation API, and it always makes sense to lock the
         // orientation of a browser Activity, so we support locking.
         if (getRequestedOrientation() == requestedActivityInfoOrientation) {
             return false;
         }
         setRequestedOrientation(requestedActivityInfoOrientation);
         return true;
     }
+
+    @Override
+    public void onScreenOrientationChanged(ScreenOrientation newOrientation) {
+        if (mFormAssistPopup != null) {
+            mFormAssistPopup.hide();
+        }
+        refreshChrome();
+    }
 }

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoScreenOrientation.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoScreenOrientation.java
@@ -8,17 +8,19 @@ package org.mozilla.gecko;
 import android.content.Context;
 import android.content.pm.ActivityInfo;
 import android.content.res.Configuration;
 import android.util.Log;
 import android.view.Surface;
 import android.view.WindowManager;
 
 import org.mozilla.gecko.annotation.WrapForJNI;
+import org.mozilla.gecko.util.ThreadUtils;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
 /*
  * Updates, locks and unlocks the screen orientation.
  *
  * Note: Replaces the OnOrientationChangeListener to avoid redundant rotation
  * event handling.
@@ -59,27 +61,50 @@ public class GeckoScreenOrientation {
     private static GeckoScreenOrientation sInstance;
     // Default rotation, used when device rotation is unknown.
     private static final int DEFAULT_ROTATION = Surface.ROTATION_0;
     // Last updated screen orientation.
     private ScreenOrientation mScreenOrientation;
     // Whether the update should notify Gecko about screen orientation changes.
     private boolean mShouldNotify = true;
 
+    public interface OrientationChangeListener {
+        void onScreenOrientationChanged(ScreenOrientation newOrientation);
+    }
+
+    private final List<OrientationChangeListener> mListeners;
+
     public static GeckoScreenOrientation getInstance() {
         if (sInstance == null) {
             sInstance = new GeckoScreenOrientation();
         }
         return sInstance;
     }
 
     private GeckoScreenOrientation() {
+        mListeners = new ArrayList<>();
         update();
     }
 
+    /**
+     * Add a listener that will be notified when the screen orientation has changed.
+     */
+    public void addListener(OrientationChangeListener aListener) {
+        ThreadUtils.assertOnUiThread();
+        mListeners.add(aListener);
+    }
+
+    /**
+     * Remove a OrientationChangeListener again.
+     */
+    public void removeListener(OrientationChangeListener aListener) {
+        ThreadUtils.assertOnUiThread();
+        mListeners.remove(aListener);
+    }
+
     /*
      * Enable Gecko screen orientation events on update.
      */
     public void enableNotifications() {
         update();
         mShouldNotify = true;
     }
 
@@ -130,16 +155,17 @@ public class GeckoScreenOrientation {
      * @return Whether the screen orientation has changed.
      */
     public boolean update(ScreenOrientation aScreenOrientation) {
         if (mScreenOrientation == aScreenOrientation) {
             return false;
         }
         mScreenOrientation = aScreenOrientation;
         Log.d(LOGTAG, "updating to new orientation " + mScreenOrientation);
+        notifyListeners(mScreenOrientation);
         if (mShouldNotify) {
             // Gecko expects a definite screen orientation, so we default to the
             // primary orientations.
             if (aScreenOrientation == ScreenOrientation.PORTRAIT) {
                 aScreenOrientation = ScreenOrientation.PORTRAIT_PRIMARY;
             } else if (aScreenOrientation == ScreenOrientation.LANDSCAPE) {
                 aScreenOrientation = ScreenOrientation.LANDSCAPE_PRIMARY;
             }
@@ -150,16 +176,33 @@ public class GeckoScreenOrientation {
                 GeckoThread.queueNativeCall(GeckoScreenOrientation.class, "onOrientationChange",
                                             aScreenOrientation.value, getAngle());
             }
         }
         GeckoAppShell.resetScreenSize();
         return true;
     }
 
+    private void notifyListeners(final ScreenOrientation newOrientation) {
+        final Runnable notifier = new Runnable() {
+            @Override
+            public void run() {
+                for (OrientationChangeListener listener : mListeners) {
+                    listener.onScreenOrientationChanged(newOrientation);
+                }
+            }
+        };
+
+        if (ThreadUtils.isOnUiThread()) {
+            notifier.run();
+        } else {
+            ThreadUtils.postToUiThread(notifier);
+        }
+    }
+
     /*
      * @return The Android orientation (Configuration.orientation).
      */
     public int getAndroidOrientation() {
         return screenOrientationToAndroidOrientation(getScreenOrientation());
     }
 
     /*