--- a/mobile/android/base/java/org/mozilla/gecko/GeckoApp.java
+++ b/mobile/android/base/java/org/mozilla/gecko/GeckoApp.java
@@ -2872,9 +2872,14 @@ public abstract class GeckoApp
         // 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 boolean isOfficial() {
+        return AppConstants.MOZILLA_OFFICIAL;
+    }
 }

--- a/mobile/android/base/moz.build
+++ b/mobile/android/base/moz.build
@@ -2,19 +2,23 @@
 # vim: set filetype=python:
 # 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/.
 
 DIRS += ['locales']
 
 GENERATED_FILES += [
+    '../geckoview/generated/preprocessed/org/mozilla/geckoview/BuildConfig.java',
     'generated/preprocessed/org/mozilla/gecko/AdjustConstants.java',
     'generated/preprocessed/org/mozilla/gecko/AppConstants.java',
 ]
+w = GENERATED_FILES['../geckoview/generated/preprocessed/org/mozilla/geckoview/BuildConfig.java']
+w.script = 'generate_build_config.py'
+w.inputs += ['../geckoview/BuildConfig.java.in']
 x = GENERATED_FILES['generated/preprocessed/org/mozilla/gecko/AdjustConstants.java']
 x.script = 'generate_build_config.py'
 x.inputs += ['AdjustConstants.java.in']
 y = GENERATED_FILES['generated/preprocessed/org/mozilla/gecko/AppConstants.java']
 y.script = 'generate_build_config.py'
 y.inputs += ['AppConstants.java.in']
 
 include('android-services.mozbuild')
@@ -35,16 +39,17 @@ constants_jar.sources += [geckoview_sour
 constants_jar.sources += ['java/org/mozilla/gecko/' + x for x in [
     'adjust/AdjustHelperInterface.java',
     'adjust/AttributionHelperListener.java',
     'db/BrowserContract.java',
     'LocaleManager.java',
     'Locales.java',
 ]]
 constants_jar.generated_sources = [
+    '../geckoview/generated/preprocessed/org/mozilla/geckoview/BuildConfig.java',
     'generated/preprocessed/org/mozilla/gecko/AdjustConstants.java',
     'generated/preprocessed/org/mozilla/gecko/AppConstants.java',
 ]
 constants_jar.extra_jars = [
     CONFIG['ANDROID_SUPPORT_ANNOTATIONS_JAR_LIB'],
     CONFIG['ANDROID_SUPPORT_V4_AAR_LIB'],
     CONFIG['ANDROID_SUPPORT_V4_AAR_INTERNAL_LIB'],
     CONFIG['ANDROID_APPCOMPAT_V7_AAR_LIB'],

new file mode 100644
--- /dev/null
+++ b/mobile/android/geckoview/BuildConfig.java.in
@@ -0,0 +1,57 @@
+//#filter substitution
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
+ * 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.geckoview;
+
+import android.os.Build;
+
+/**
+ * A collection of constants that pertain to the build state of the GeckoView
+ * library, sourced from build-time definitions.  This is a partial Java-side
+ * substitute for nsIXULAppInfo, amongst other things.
+ *
+ * See also SysInfo.java, which includes some of the values available from
+ * nsSystemInfo inside Gecko.
+ */
+public class BuildConfig {
+    public static final String GRE_MILESTONE = "@GRE_MILESTONE@";
+
+    public static final String MOZ_APP_ABI = "@MOZ_APP_ABI@";
+    public static final String MOZ_APP_BASENAME = "@MOZ_APP_BASENAME@";
+
+    // For the benefit of future archaeologists:
+    // GRE_BUILDID is exactly the same as MOZ_APP_BUILDID unless you're running
+    // on XULRunner, which is never the case on Android.
+    public static final String MOZ_APP_BUILDID = "@MOZ_BUILDID@";
+    public static final String MOZ_APP_ID = "@MOZ_APP_ID@";
+    public static final String MOZ_APP_NAME = "@MOZ_APP_NAME@";
+    public static final String MOZ_APP_VENDOR = "@MOZ_APP_VENDOR@";
+    public static final String MOZ_APP_VERSION = "@MOZ_APP_VERSION@";
+    public static final String MOZ_APP_DISPLAYNAME = "@MOZ_APP_DISPLAYNAME@";
+    public static final String MOZ_APP_UA_NAME = "@MOZ_APP_UA_NAME@";
+
+    // MOZILLA_VERSION is already quoted when it gets substituted in. If we
+    // add additional quotes we end up with ""x.y"", which is a syntax error.
+    public static final String MOZILLA_VERSION = @MOZILLA_VERSION@;
+    public static final String OMNIJAR_NAME = "@OMNIJAR_NAME@";
+
+    public static final String USER_AGENT_GECKOVIEW_MOBILE = "Mozilla/5.0 (Android " +
+        Build.VERSION.RELEASE + "; Mobile; rv:" +
+        MOZ_APP_VERSION + ") Gecko/" +
+        MOZ_APP_VERSION + " GeckoView/" +
+        MOZ_APP_VERSION;
+
+    public static final String USER_AGENT_GECKOVIEW_TABLET = "Mozilla/5.0 (Android " +
+        Build.VERSION.RELEASE + "; Tablet; rv:" +
+        MOZ_APP_VERSION + ") Gecko/" +
+        MOZ_APP_VERSION + " GeckoView/" +
+        MOZ_APP_VERSION;
+
+    /**
+     * Target CPU architecture: "armeabi-v7a", "x86, "mips", ..
+     */
+    public static final String ANDROID_CPU_ARCH = "@ANDROID_CPU_ARCH@";
+}

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/AndroidGamepadManager.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/AndroidGamepadManager.java
@@ -5,17 +5,16 @@
 
 package org.mozilla.gecko;
 
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Timer;
 import java.util.TimerTask;
 
-import org.mozilla.gecko.AppConstants.Versions;
 import org.mozilla.gecko.annotation.WrapForJNI;
 import org.mozilla.gecko.util.GamepadUtils;
 import org.mozilla.gecko.util.ThreadUtils;
 
 import android.content.Context;
 import android.hardware.input.InputManager;
 import android.os.Build;
 import android.util.SparseArray;

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/BaseGeckoInterface.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/BaseGeckoInterface.java
@@ -1,16 +1,17 @@
 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
  * 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.util.HardwareUtils;
+import org.mozilla.geckoview.BuildConfig;
 
 import android.app.Activity;
 import android.content.Context;
 import android.view.View;
 import android.widget.AbsoluteLayout;
 
 public class BaseGeckoInterface implements GeckoAppShell.GeckoInterface {
     // Bug 908744: Implement GeckoEventListener
@@ -45,18 +46,18 @@ public class BaseGeckoInterface implemen
     @Override
     public Activity getActivity() {
         // By default, GeckoView consumers do not have a distinguished current foreground Activity.
         return null;
     }
 
     @Override
     public String getDefaultUAString() {
-        return HardwareUtils.isTablet() ? AppConstants.USER_AGENT_FENNEC_TABLET :
-                                          AppConstants.USER_AGENT_FENNEC_MOBILE;
+        return HardwareUtils.isTablet() ? BuildConfig.USER_AGENT_GECKOVIEW_TABLET :
+                                          BuildConfig.USER_AGENT_GECKOVIEW_MOBILE;
     }
 
     // Bug 908775: Implement this
     @Override
     public void doRestart() {}
 
     @Override
     public void setFullScreen(final boolean fullscreen) {
@@ -157,9 +158,15 @@ public class BaseGeckoInterface implemen
         // By default, use the GeckoView-specific chrome URI.
         return "chrome://browser/content/geckoview.xul";
     }
 
     @Override
     public boolean isForegrounded() {
         return false;
     }
+
+    @Override
+    public boolean isOfficial() {
+        // By default, GeckoView consumers are not official Mozilla applications.
+        return false;
+    }
 }

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoAccessibility.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoAccessibility.java
@@ -2,17 +2,16 @@
  * 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.json.JSONException;
 import org.json.JSONObject;
-import org.mozilla.gecko.AppConstants.Versions;
 import org.mozilla.gecko.util.GeckoBundle;
 import org.mozilla.gecko.util.ThreadUtils;
 import org.mozilla.gecko.util.UIAsyncTask;
 
 import android.content.Context;
 import android.graphics.Rect;
 import android.os.Build;
 import android.os.Bundle;

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoAppShell.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoAppShell.java
@@ -1819,16 +1819,23 @@ public class GeckoAppShell
         /**
          * URI of the underlying chrome window to be opened, or null to use the default GeckoView
          * XUL container <tt>chrome://browser/content/geckoview.xul</tt>.  See
          * <a href="https://developer.mozilla.org/en/docs/toolkit.defaultChromeURI">https://developer.mozilla.org/en/docs/toolkit.defaultChromeURI</a>
          *
          * @return URI or null.
          */
         String getDefaultChromeURI();
+
+        /**
+         * Is this an official Mozilla application, like Firefox or Thunderbird?
+         *
+         * @return true if MOZILLA_OFFICIAL.
+         */
+        boolean isOfficial();
     };
 
     private static GeckoInterface sGeckoInterface;
 
     public static GeckoInterface getGeckoInterface() {
         return sGeckoInterface;
     }
 

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoEditable.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoEditable.java
@@ -9,17 +9,16 @@ import java.lang.reflect.Array;
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationHandler;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Proxy;
 import java.util.concurrent.ConcurrentLinkedQueue;
 
 import org.json.JSONObject;
-import org.mozilla.gecko.AppConstants.Versions;
 import org.mozilla.gecko.annotation.WrapForJNI;
 import org.mozilla.gecko.gfx.LayerView;
 import org.mozilla.gecko.mozglue.JNIObject;
 import org.mozilla.gecko.util.ThreadUtils;
 import org.mozilla.gecko.util.ThreadUtils.AssertBehavior;
 
 import android.graphics.RectF;
 import android.os.Handler;

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoInputConnection.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoInputConnection.java
@@ -5,17 +5,16 @@
 
 package org.mozilla.gecko;
 
 import java.lang.reflect.InvocationHandler;
 import java.lang.reflect.Method;
 import java.lang.reflect.Proxy;
 import java.util.concurrent.SynchronousQueue;
 
-import org.mozilla.gecko.AppConstants.Versions;
 import org.mozilla.gecko.gfx.DynamicToolbarAnimator;
 import org.mozilla.gecko.util.Clipboard;
 import org.mozilla.gecko.util.GamepadUtils;
 import org.mozilla.gecko.util.ThreadUtils;
 import org.mozilla.gecko.util.ThreadUtils.AssertBehavior;
 
 import android.annotation.SuppressLint;
 import android.annotation.TargetApi;

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoProfile.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoProfile.java
@@ -46,18 +46,18 @@ public final class GeckoProfile {
     private static final String CLIENT_ID_FILE_PATH = "datareporting/state.json";
     private static final String FHR_CLIENT_ID_FILE_PATH = "healthreport/state.json";
     // In the client ID file, the attribute title in the JSON object containing the client ID value.
     private static final String CLIENT_ID_JSON_ATTR = "clientID";
 
     private static final String TIMES_PATH = "times.json";
     private static final String PROFILE_CREATION_DATE_JSON_ATTR = "created";
 
-    // Only tests should need to do this.
-    // We can default this to AppConstants.RELEASE_OR_BETA once we fix Bug 1069687.
+    // Only tests should need to do this.  We can remove this entirely once we
+    // fix Bug 1069687.
     private static volatile boolean sAcceptDirectoryChanges = true;
 
     @RobocopTarget
     public static void enableDirectoryChanges() {
         Log.w(LOGTAG, "Directory changes should only be enabled for tests. And even then it's a bad idea.");
         sAcceptDirectoryChanges = true;
     }
 
@@ -222,19 +222,16 @@ public final class GeckoProfile {
                 args = null;
             }
 
             return GeckoProfile.initFromArgs(context, args);
 
         } else if (profileName == null) {
             // If only profile dir was passed in, use custom (anonymous) profile.
             profileName = CUSTOM_PROFILE;
-
-        } else if (AppConstants.DEBUG_BUILD) {
-            Log.v(LOGTAG, "Fetching profile: '" + profileName + "', '" + profileDir + "'");
         }
 
         // We require the profile dir to exist if specified, so create it here if needed.
         final boolean init = profileDir != null && profileDir.mkdirs();
 
         // Actually try to look up the profile.
         GeckoProfile profile = sProfileCache.get(profileName);
         GeckoProfile newProfile = null;
@@ -262,21 +259,16 @@ public final class GeckoProfile {
             } catch (final IOException e) {
             }
 
             if (!consistent) {
                 if (!sAcceptDirectoryChanges || !profileDir.isDirectory()) {
                     throw new IllegalStateException(
                             "Refusing to reuse profile with a different directory.");
                 }
-
-                if (AppConstants.RELEASE_OR_BETA) {
-                    Log.e(LOGTAG, "Release build trying to switch out profile dir. " +
-                                  "This is an error, but let's do what we can.");
-                }
                 profile.setDir(profileDir);
             }
         }
 
         if (init) {
             // Initialize the profile directory if we had to create it.
             profile.enqueueInitialization(profileDir);
         }

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoThread.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/GeckoThread.java
@@ -461,17 +461,18 @@ public class GeckoThread extends Thread 
         args.add(apkPath);
 
         addCustomProfileArg(mArgs, args);
 
         // In un-official builds, we want to load Javascript resources fresh
         // with each build.  In official builds, the startup cache is purged by
         // the buildid mechanism, but most un-official builds don't bump the
         // buildid, so we purge here instead.
-        if (!AppConstants.MOZILLA_OFFICIAL) {
+        final GeckoAppShell.GeckoInterface gi = GeckoAppShell.getGeckoInterface();
+        if (gi == null || !gi.isOfficial()) {
             Log.w(LOGTAG, "STARTUP PERFORMANCE WARNING: un-official build: purging the " +
                           "startup (JavaScript) caches.");
             args.add("-purgecaches");
         }
 
         return args.toArray(new String[args.size()]);
     }
 
@@ -535,19 +536,19 @@ public class GeckoThread extends Thread 
         ThreadUtils.postToUiThread(new Runnable() {
             @Override public void run() {
                 registerUiThread();
             }
         });
 
         Log.w(LOGTAG, "zerdatime " + SystemClock.uptimeMillis() + " - runGecko");
 
-        if (!AppConstants.MOZILLA_OFFICIAL) {
-            String msg = new String("RunGecko - args =" + TextUtils.join(" ", args));
-            Log.i(LOGTAG, msg);
+        final GeckoAppShell.GeckoInterface gi = GeckoAppShell.getGeckoInterface();
+        if (gi == null || !gi.isOfficial()) {
+            Log.i(LOGTAG, "RunGecko - args = " + args);
         }
 
         // And go.
         GeckoLoader.nativeRun(args, mCrashFileDescriptor, mIPCFileDescriptor);
 
         // And... we're done.
         setState(State.EXITED);
 

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/InputMethods.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/InputMethods.java
@@ -2,18 +2,16 @@
  * 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 java.util.Collection;
 
-import org.mozilla.gecko.AppConstants.Versions;
-
 import android.content.Context;
 import android.os.Build;
 import android.provider.Settings.Secure;
 import android.view.inputmethod.InputMethodInfo;
 import android.view.inputmethod.InputMethodManager;
 
 final public class InputMethods {
     public static final String METHOD_ANDROID_LATINIME = "com.android.inputmethod.latin/.LatinIME";

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/SysInfo.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/SysInfo.java
@@ -13,18 +13,18 @@ import java.io.FileFilter;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 
 import java.util.regex.Pattern;
 
 /**
  * A collection of system info values, broadly mirroring a subset of
- * nsSystemInfo. See also the constants in AppConstants, which reflect
- * much of nsIXULAppInfo.
+ * nsSystemInfo. See also the constants in org.mozilla.geckoview.BuildConfig,
+ * which reflect much of nsIXULAppInfo.
  */
 // Normally, we'd annotate with @RobocopTarget.  Since SysInfo is compiled
 // before RobocopTarget, we instead add o.m.g.SysInfo directly to the Proguard
 // configuration.
 public final class SysInfo {
     private static final String LOG_TAG = "GeckoSysInfo";
 
     // Number of bytes of /proc/meminfo to read in one go.

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/DynamicToolbarAnimator.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/DynamicToolbarAnimator.java
@@ -1,16 +1,15 @@
 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
  * 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.gfx;
 
-import org.mozilla.gecko.AppConstants;
 import org.mozilla.gecko.PrefsHelper;
 import org.mozilla.gecko.util.FloatUtils;
 import org.mozilla.gecko.util.ThreadUtils;
 
 import android.graphics.PointF;
 import android.support.v4.view.ViewCompat;
 import android.util.Log;
 import android.view.MotionEvent;

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/GeckoLayerClient.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/GeckoLayerClient.java
@@ -5,17 +5,16 @@
 
 package org.mozilla.gecko.gfx;
 
 import org.mozilla.gecko.annotation.RobocopTarget;
 import org.mozilla.gecko.annotation.WrapForJNI;
 import org.mozilla.gecko.GeckoAppShell;
 import org.mozilla.gecko.gfx.LayerView.DrawListener;
 import org.mozilla.gecko.util.FloatUtils;
-import org.mozilla.gecko.AppConstants;
 
 import android.content.Context;
 import android.graphics.Color;
 import android.graphics.Matrix;
 import android.graphics.PointF;
 import android.graphics.RectF;
 import android.os.SystemClock;
 import android.util.DisplayMetrics;

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/LayerRenderer.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/LayerRenderer.java
@@ -1,16 +1,15 @@
 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
  * 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.gfx;
 
-import org.mozilla.gecko.AppConstants;
 import org.mozilla.gecko.GeckoAppShell;
 import org.mozilla.gecko.mozglue.DirectBufferAllocator;
 
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Matrix;

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/LayerView.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/LayerView.java
@@ -6,18 +6,16 @@
 package org.mozilla.gecko.gfx;
 
 import java.nio.ByteBuffer;
 import java.nio.IntBuffer;
 
 import org.mozilla.gecko.AndroidGamepadManager;
 import org.mozilla.gecko.annotation.RobocopTarget;
 import org.mozilla.gecko.annotation.WrapForJNI;
-import org.mozilla.gecko.AppConstants;
-import org.mozilla.gecko.AppConstants.Versions;
 import org.mozilla.gecko.GeckoAccessibility;
 import org.mozilla.gecko.GeckoAppShell;
 import org.mozilla.gecko.GeckoThread;
 import org.mozilla.gecko.mozglue.JNIObject;
 import org.mozilla.gecko.util.ThreadUtils;
 
 import android.content.Context;
 import android.graphics.Canvas;

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/OverscrollEdgeEffect.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/gfx/OverscrollEdgeEffect.java
@@ -1,17 +1,15 @@
 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
  * 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.gfx;
 
-import org.mozilla.gecko.AppConstants.Versions;
-
 import android.content.Context;
 import android.graphics.Canvas;
 import android.graphics.Paint;
 import android.graphics.PointF;
 import android.graphics.PorterDuff;
 import android.graphics.PorterDuffXfermode;
 import android.os.Build;
 import android.widget.EdgeEffect;

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/mozglue/GeckoLoader.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/mozglue/GeckoLoader.java
@@ -19,17 +19,17 @@ import android.content.Context;
 import android.content.Intent;
 import android.os.Build;
 import android.os.Environment;
 import java.util.ArrayList;
 import android.util.Log;
 
 import org.mozilla.gecko.annotation.JNITarget;
 import org.mozilla.gecko.annotation.RobocopTarget;
-import org.mozilla.gecko.AppConstants;
+import org.mozilla.geckoview.BuildConfig;
 
 public final class GeckoLoader {
     private static final String LOGTAG = "GeckoLoader";
 
     private static volatile SafeIntent sIntent;
     private static File sCacheFile;
     private static File sGREDir;
 
@@ -352,17 +352,17 @@ public final class GeckoLoader {
 
     private static String getLoadDiagnostics(final Context context, final String lib) {
         final String androidPackageName = context.getPackageName();
 
         final StringBuilder message = new StringBuilder("LOAD ");
         message.append(lib);
 
         // These might differ. If so, we know why the library won't load!
-        message.append(": ABI: " + AppConstants.MOZ_APP_ABI + ", " + getCPUABI());
+        message.append(": ABI: " + BuildConfig.MOZ_APP_ABI + ", " + getCPUABI());
         message.append(": Data: " + context.getApplicationInfo().dataDir);
         try {
             final boolean appLibExists = new File("/data/app-lib/" + androidPackageName + "/lib" + lib + ".so").exists();
             final boolean dataDataExists = new File("/data/data/" + androidPackageName + "/lib/lib" + lib + ".so").exists();
             message.append(", ax=" + appLibExists);
             message.append(", ddx=" + dataDataExists);
         } catch (Throwable e) {
             message.append(": ax/ddx fail, ");

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/sqlite/MatrixBlobCursor.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/sqlite/MatrixBlobCursor.java
@@ -16,17 +16,16 @@
  */
 
 package org.mozilla.gecko.sqlite;
 
 import java.nio.ByteBuffer;
 import java.util.ArrayList;
 
 import org.mozilla.gecko.annotation.JNITarget;
-import org.mozilla.gecko.AppConstants;
 
 import android.database.AbstractCursor;
 import android.database.CursorIndexOutOfBoundsException;
 import android.util.Log;
 
 /**
  * A mutable cursor implementation backed by an array of {@code Object}s. Use
  * {@link #newRow()} to add rows. Automatically expands internal capacity
@@ -61,19 +60,17 @@ public class MatrixBlobCursor extends Ab
         this.columnNames = columnNames;
         this.columnCount = columnNames.length;
 
         if (initialCapacity < 1) {
             initialCapacity = 1;
         }
 
         this.data = new Object[columnCount * initialCapacity];
-        if (AppConstants.DEBUG_BUILD) {
-            this.allocationStack = new Throwable("allocationStack");
-        }
+        this.allocationStack = new Throwable("allocationStack");
     }
 
     /**
      * Constructs a new cursor.
      *
      * @param columnNames names of the columns, the ordering of which
      *  determines column ordering elsewhere in this cursor
      */
@@ -350,17 +347,15 @@ public class MatrixBlobCursor extends Ab
 
     @Override
     public boolean isNull(int column) {
         return get(column) == null;
     }
 
     @Override
     protected void finalize() {
-        if (AppConstants.DEBUG_BUILD) {
-            if (!isClosed()) {
-                Log.e(LOGTAG, "Cursor finalized without being closed", this.allocationStack);
-            }
+        if (!isClosed()) {
+            Log.e(LOGTAG, "Cursor finalized without being closed", this.allocationStack);
         }
 
         super.finalize();
     }
 }

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/ActivityUtils.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/ActivityUtils.java
@@ -7,18 +7,16 @@ package org.mozilla.gecko.util;
 
 import android.app.Activity;
 import android.content.Intent;
 import android.os.Build;
 import android.view.View;
 import android.view.Window;
 import android.view.WindowManager;
 
-import org.mozilla.gecko.AppConstants.Versions;
-
 public class ActivityUtils {
     private ActivityUtils() {
     }
 
     public static void setFullScreen(Activity activity, boolean fullscreen) {
         // Hide/show the system notification bar
         Window window = activity.getWindow();
 

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/Clipboard.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/Clipboard.java
@@ -2,17 +2,16 @@
  * 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.util;
 
 import java.util.concurrent.SynchronousQueue;
 
 import org.mozilla.gecko.annotation.WrapForJNI;
-import org.mozilla.gecko.AppConstants.Versions;
 
 import android.content.ClipData;
 import android.content.Context;
 import android.util.Log;
 
 public final class Clipboard {
     // Volatile but not synchronized: we don't care about the race condition in
     // init, because both app contexts will be the same, but we do care about a

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/GeckoJarReader.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/GeckoJarReader.java
@@ -4,20 +4,21 @@
 
 package org.mozilla.gecko.util;
 
 import android.content.Context;
 import android.content.res.Resources;
 import android.graphics.Bitmap;
 import android.graphics.drawable.BitmapDrawable;
 import android.util.Log;
+
 import org.mozilla.gecko.annotation.RobocopTarget;
-import org.mozilla.gecko.AppConstants;
 import org.mozilla.gecko.mozglue.GeckoLoader;
 import org.mozilla.gecko.mozglue.NativeZip;
+import org.mozilla.geckoview.BuildConfig;
 
 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
@@ -251,11 +252,11 @@ public final class GeckoJarReader {
     /**
      * Encodes its resource path correctly.
      */
     @RobocopTarget
     public static String computeJarURI(String resourcePath, String pathInsideJAR) {
         final String resURI = new File(resourcePath).toURI().toString();
 
         // TODO: do we need to encode the file path, too?
-        return "jar:jar:" + resURI + "!/" + AppConstants.OMNIJAR_NAME + "!/" + pathInsideJAR;
+        return "jar:jar:" + resURI + "!/" + BuildConfig.OMNIJAR_NAME + "!/" + pathInsideJAR;
     }
 }

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/HardwareCodecCapabilityUtils.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/HardwareCodecCapabilityUtils.java
@@ -2,17 +2,16 @@
  *  * 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.util;
 
 import org.mozilla.gecko.annotation.WrapForJNI;
-import org.mozilla.gecko.AppConstants.Versions;
 
 import android.media.MediaCodec;
 import android.media.MediaCodecInfo;
 import android.media.MediaCodecInfo.CodecCapabilities;
 import android.media.MediaCodecList;
 import android.os.Build;
 import android.util.Log;
 

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/HardwareUtils.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/HardwareUtils.java
@@ -1,24 +1,25 @@
 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
  * 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.util;
 
-import org.mozilla.gecko.AppConstants;
 import org.mozilla.gecko.SysInfo;
 
 import android.content.Context;
 import android.content.pm.PackageManager;
 import android.content.res.Configuration;
 import android.os.Build;
 import android.util.Log;
-import android.view.ViewConfiguration;
+
+import org.mozilla.gecko.SysInfo;
+import org.mozilla.geckoview.BuildConfig;
 
 public final class HardwareUtils {
     private static final String LOGTAG = "GeckoHardwareUtils";
 
     private static final boolean IS_AMAZON_DEVICE = Build.MANUFACTURER.equalsIgnoreCase("Amazon");
     public static final boolean IS_KINDLE_DEVICE = IS_AMAZON_DEVICE &&
                                                    (Build.MODEL.equals("Kindle Fire") ||
                                                     Build.MODEL.startsWith("KF"));
@@ -81,24 +82,24 @@ public final class HardwareUtils {
     /**
      * @return false if the current system is not supported (e.g. APK/system ABI mismatch).
      */
     public static boolean isSupportedSystem() {
         // See http://developer.android.com/ndk/guides/abis.html
         boolean isSystemARM = Build.CPU_ABI != null && Build.CPU_ABI.startsWith("arm");
         boolean isSystemX86 = Build.CPU_ABI != null && Build.CPU_ABI.startsWith("x86");
 
-        boolean isAppARM = AppConstants.ANDROID_CPU_ARCH.startsWith("arm");
-        boolean isAppX86 = AppConstants.ANDROID_CPU_ARCH.startsWith("x86");
+        boolean isAppARM = BuildConfig.ANDROID_CPU_ARCH.startsWith("arm");
+        boolean isAppX86 = BuildConfig.ANDROID_CPU_ARCH.startsWith("x86");
 
         // Only reject known incompatible ABIs. Better safe than sorry.
         if ((isSystemX86 && isAppARM) || (isSystemARM && isAppX86)) {
             return false;
         }
 
         if ((isSystemX86 && isAppX86) || (isSystemARM && isAppARM)) {
             return true;
         }
 
-        Log.w(LOGTAG, "Unknown app/system ABI combination: " + AppConstants.MOZ_APP_ABI + " / " + Build.CPU_ABI);
+        Log.w(LOGTAG, "Unknown app/system ABI combination: " + BuildConfig.MOZ_APP_ABI + " / " + Build.CPU_ABI);
         return true;
     }
 }

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/PrefUtils.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/PrefUtils.java
@@ -5,17 +5,16 @@
 
 package org.mozilla.gecko.util;
 
 import java.util.HashSet;
 import java.util.Set;
 
 import org.json.JSONArray;
 import org.json.JSONException;
-import org.mozilla.gecko.AppConstants.Versions;
 
 import android.content.SharedPreferences;
 import android.util.Log;
 
 
 public class PrefUtils {
     private static final String LOGTAG = "GeckoPrefUtils";
 

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/StringUtils.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/StringUtils.java
@@ -4,18 +4,16 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 package org.mozilla.gecko.util;
 
 import android.net.Uri;
 import android.support.annotation.NonNull;
 import android.text.TextUtils;
 
-import org.mozilla.gecko.AppConstants.Versions;
-
 import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Set;
 
 public class StringUtils {
     private static final String LOGTAG = "GeckoStringUtils";
 

--- a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/WindowUtils.java
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/WindowUtils.java
@@ -1,17 +1,15 @@
 /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
  * 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.util;
 
-import org.mozilla.gecko.AppConstants.Versions;
-
 import android.content.Context;
 import android.os.Build;
 import android.util.DisplayMetrics;
 import android.util.Log;
 import android.view.Display;
 import android.view.WindowManager;
 
 import java.lang.reflect.Method;