--- a/mobile/android/base/Makefile.in
+++ b/mobile/android/base/Makefile.in
@@ -25,16 +25,17 @@ GARBAGE_DIRS += classes db jars res sync
 generated_resources := \
   AndroidManifest.xml \
   res/raw/browsersearch.json \
   res/raw/suggestedsites.json \
   res/values/strings.xml \
   $(NULL)
 
 generated_files := \
+  ../geckoview/generated/preprocessed/org/mozilla/geckoview/BuildConfig.java \
   AndroidManifest.xml \
   generated/preprocessed/org/mozilla/gecko/AdjustConstants.java \
   generated/preprocessed/org/mozilla/gecko/AppConstants.java \
   generated/preprocessed/org/mozilla/gecko/MmaConstants.java \
   $(NULL)
 
 gradle_dir := $(topobjdir)/gradle/build/mobile/android
 

--- a/mobile/android/base/moz.build
+++ b/mobile/android/base/moz.build
@@ -107,21 +107,25 @@ with Files('../app/src/*/res/menu/*activ
     BUG_COMPONENT = ('Firefox for Android', 'Awesomescreen')
 
 with Files('../app/src/*/res/menu/browsersearch_contextmenu.xml'):
     BUG_COMPONENT = ('Firefox for Android', 'Awesomescreen')
 
 DIRS += ['locales']
 
 GENERATED_FILES += [
+    '../geckoview/generated/preprocessed/org/mozilla/geckoview/BuildConfig.java',
     'AndroidManifest.xml',
     'generated/preprocessed/org/mozilla/gecko/AdjustConstants.java',
     'generated/preprocessed/org/mozilla/gecko/AppConstants.java',
     'generated/preprocessed/org/mozilla/gecko/MmaConstants.java',
 ]
+w = GENERATED_FILES['../geckoview/generated/preprocessed/org/mozilla/geckoview/BuildConfig.java']
+w.script = 'generate_build_config.py:generate_java'
+w.inputs += ['../geckoview/BuildConfig.java.in']
 x = GENERATED_FILES['generated/preprocessed/org/mozilla/gecko/AdjustConstants.java']
 x.script = 'generate_build_config.py:generate_java'
 x.inputs += ['AdjustConstants.java.in']
 y = GENERATED_FILES['generated/preprocessed/org/mozilla/gecko/AppConstants.java']
 y.script = 'generate_build_config.py:generate_java'
 y.inputs += ['AppConstants.java.in']
 y = GENERATED_FILES['generated/preprocessed/org/mozilla/gecko/MmaConstants.java']
 y.script = 'generate_build_config.py:generate_java'

new file mode 100644
--- /dev/null
+++ b/mobile/android/geckoview/BuildConfig.java.in
@@ -0,0 +1,106 @@
+//#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", "arm64-v8a", "x86", "mips", ..
+     */
+    public static final String ANDROID_CPU_ARCH = "@ANDROID_CPU_ARCH@";
+
+    public static final String MOZ_UPDATE_CHANNEL = "@MOZ_UPDATE_CHANNEL@";
+
+    public static final int MIN_SDK_VERSION = @MOZ_ANDROID_MIN_SDK_VERSION@;
+
+    // Is the underlying compiled C/C++ code compiled with --enable-debug?
+    public static final boolean DEBUG_BUILD =
+//#ifdef MOZ_DEBUG
+    true;
+//#else
+    false;
+//#endif
+
+    // See this wiki page for more details about channel specific build defines:
+    // https://wiki.mozilla.org/Platform/Channel-specific_build_defines
+    // This makes no sense for GeckoView and should be removed as soon as possible.
+    public static final boolean RELEASE_OR_BETA =
+//#ifdef RELEASE_OR_BETA
+    true;
+//#else
+    false;
+//#endif
+
+    // This makes no sense for GeckoView and should be removed as soon as possible.
+    public static final boolean NIGHTLY_BUILD =
+//#ifdef NIGHTLY_BUILD
+    true;
+//#else
+    false;
+//#endif
+
+    // This makes no sense for GeckoView and should be removed as soon as possible.
+    public static final boolean MOZ_CRASHREPORTER =
+//#ifdef MOZ_CRASHREPORTER
+    true;
+//#else
+    false;
+//#endif
+
+    // Official corresponds, roughly, to whether this build is performed on
+    // Mozilla's continuous integration infrastructure. You should disable
+    // developer-only functionality when this flag is set.
+    // This makes no sense for GeckoView and should be removed as soon as possible.
+    public static final boolean MOZILLA_OFFICIAL =
+//#ifdef MOZILLA_OFFICIAL
+    true;
+//#else
+    false;
+//#endif
+}

--- a/mobile/android/geckoview/build.gradle
+++ b/mobile/android/geckoview/build.gradle
@@ -48,16 +48,18 @@ android {
         manifestPlaceholders = project.ext.manifestPlaceholders
 
         versionCode computeVersionCode()
         versionName "${mozconfig.substs.MOZ_APP_VERSION}-${mozconfig.substs.MOZ_UPDATE_CHANNEL}"
         consumerProguardFiles 'proguard-rules.txt'
 
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
 
+        // TODO: ensure these fields always agree with mobile/android/geckoview/BuildConfig.java.in,
+        // either by diffing the processed files or by generating the output from a single source.
         buildConfigField 'String', "GRE_MILESTONE", "\"${mozconfig.substs.GRE_MILESTONE}\""
         // This should really come from the included binaries, but that's not easy.
         buildConfigField 'String', "MOZ_APP_ABI", mozconfig.substs['COMPILE_ENVIRONMENT'] ? "\"${ mozconfig.substs.TARGET_XPCOM_ABI}\"" : '"arm-eabi-gcc3"';
         buildConfigField 'String', "MOZ_APP_BASENAME", "\"${mozconfig.substs.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.

--- a/python/mozbuild/mozbuild/backend/recursivemake.py
+++ b/python/mozbuild/mozbuild/backend/recursivemake.py
@@ -24,16 +24,20 @@ from mozbuild.frontend.context import (
     AbsolutePath,
     Path,
     RenamedSourcePath,
     SourcePath,
     ObjDirPath,
 )
 from .common import CommonBackend
 from ..frontend.data import (
+    AndroidAssetsDirs,
+    AndroidResDirs,
+    AndroidExtraResDirs,
+    AndroidExtraPackages,
     BaseLibrary,
     BaseProgram,
     ChromeManifestEntry,
     ComputedFlags,
     ConfigFileSubstitution,
     ContextDerived,
     ContextWrapped,
     Defines,

--- a/python/mozbuild/mozbuild/frontend/data.py
+++ b/python/mozbuild/mozbuild/frontend/data.py
@@ -1128,16 +1128,69 @@ class GeneratedFile(ContextDerived):
             '.inc',
             '.py',
             '.rs',
             'new', # 'new' is an output from make-stl-wrappers.py
         )
         self.required_for_compile = any(f.endswith(suffixes) for f in self.outputs)
 
 
+class AndroidResDirs(ContextDerived):
+    """Represents Android resource directories."""
+
+    __slots__ = (
+        'paths',
+    )
+
+    def __init__(self, context, paths):
+        ContextDerived.__init__(self, context)
+        self.paths = paths
+
+
+class AndroidAssetsDirs(ContextDerived):
+    """Represents Android assets directories."""
+
+    __slots__ = (
+        'paths',
+    )
+
+    def __init__(self, context, paths):
+        ContextDerived.__init__(self, context)
+        self.paths = paths
+
+
+class AndroidExtraResDirs(ContextDerived):
+    """Represents Android extra resource directories.
+
+    Extra resources are resources provided by libraries and including in a
+    packaged APK, but not otherwise redistributed.  In practice, this means
+    resources included in Fennec but not in GeckoView.
+    """
+
+    __slots__ = (
+        'paths',
+    )
+
+    def __init__(self, context, paths):
+        ContextDerived.__init__(self, context)
+        self.paths = paths
+
+
+class AndroidExtraPackages(ContextDerived):
+    """Represents Android extra packages."""
+
+    __slots__ = (
+        'packages',
+    )
+
+    def __init__(self, context, packages):
+        ContextDerived.__init__(self, context)
+        self.packages = packages
+
+
 class ChromeManifestEntry(ContextDerived):
     """Represents a chrome.manifest entry."""
 
     __slots__ = (
         'path',
         'entry',
     )
 

--- a/python/mozbuild/mozbuild/frontend/emitter.py
+++ b/python/mozbuild/mozbuild/frontend/emitter.py
@@ -18,16 +18,20 @@ from mozbuild.util import (
     OrderedDefaultDict,
 )
 
 import mozpack.path as mozpath
 import mozinfo
 import pytoml
 
 from .data import (
+    AndroidAssetsDirs,
+    AndroidExtraPackages,
+    AndroidExtraResDirs,
+    AndroidResDirs,
     BaseRustProgram,
     BaseSources,
     ChromeManifestEntry,
     ComputedFlags,
     ConfigFileSubstitution,
     ContextWrapped,
     Defines,
     DirectoryTraversal,