diff -r 000000000000 -r 6474c204b198 mobile/android/base/webapp/Allocator.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mobile/android/base/webapp/Allocator.java	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,190 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; 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.webapp;
+
+import java.util.ArrayList;
+
+import org.mozilla.gecko.GeckoAppShell;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.content.SharedPreferences.Editor;
+import android.util.Log;
+
+public class Allocator {
+
+    private final String LOGTAG = "GeckoWebappAllocator";
+
+    private static final String PREFIX_ORIGIN = "webapp-origin-";
+    private static final String PREFIX_PACKAGE_NAME = "webapp-package-name-";
+
+    // These prefixes are for prefs used by the old shortcut-based runtime.
+    // We define them here so maybeMigrateOldPrefs can migrate them to their
+    // new equivalents if this app was originally installed as a shortcut.
+    // Maybe we can remove this code in the future!
+    private static final String PREFIX_OLD_APP = "app";
+    private static final String PREFIX_OLD_ICON = "icon";
+
+    // The number of Webapp# and WEBAPP# activities/apps/intents
+    private final static int MAX_WEB_APPS = 100;
+
+    protected static Allocator sInstance = null;
+    public static Allocator getInstance() {
+        return getInstance(GeckoAppShell.getContext());
+    }
+
+    public static synchronized Allocator getInstance(Context cx) {
+        if (sInstance == null) {
+            sInstance = new Allocator(cx);
+        }
+
+        return sInstance;
+    }
+
+    SharedPreferences mPrefs;
+
+    protected Allocator(Context context) {
+        mPrefs = context.getSharedPreferences("webapps", Context.MODE_PRIVATE | Context.MODE_MULTI_PROCESS);
+    }
+
+    private static String appKey(int index) {
+        return PREFIX_PACKAGE_NAME + index;
+    }
+
+    public static String iconKey(int index) {
+        return "web-app-color-" + index;
+    }
+
+    public static String originKey(int i) {
+        return PREFIX_ORIGIN + i;
+    }
+
+    private static String oldAppKey(int index) {
+        return PREFIX_OLD_APP + index;
+    }
+
+    private static String oldIconKey(int index) {
+        return PREFIX_OLD_ICON + index;
+    }
+
+    private static void save(Editor editor) {
+        // Use SharedPreferences.Editor.apply() where available and commit()
+        // where it isn't.  We could also use a background thread with commit(),
+        // but our callers might expect the changes we make to be available
+        // immediately, so we instead take the commit() performance hit
+        // on the small percentage of extant devices that don't support apply().
+        if (android.os.Build.VERSION.SDK_INT > 8) {
+            editor.apply();
+        } else {
+            editor.commit();
+        }
+    }
+
+    public ArrayList<String> getInstalledPackageNames() {
+        ArrayList<String> installedPackages = new ArrayList<String>();
+
+        for (int i = 0; i < MAX_WEB_APPS; ++i) {
+            if (mPrefs.contains(appKey(i))) {
+                installedPackages.add(mPrefs.getString(appKey(i), ""));
+            }
+        }
+        return installedPackages;
+    }
+
+    public synchronized int findOrAllocatePackage(final String packageName) {
+        int index = getIndexForApp(packageName);
+        if (index != -1)
+            return index;
+
+        for (int i = 0; i < MAX_WEB_APPS; ++i) {
+            if (!mPrefs.contains(appKey(i))) {
+                // found unused index i
+                putPackageName(i, packageName);
+                return i;
+            }
+        }
+
+        // no more apps!
+        return -1;
+    }
+
+    public synchronized void putPackageName(final int index, final String packageName) {
+        save(mPrefs.edit().putString(appKey(index), packageName));
+    }
+
+    public void updateColor(int index, int color) {
+        save(mPrefs.edit().putInt(iconKey(index), color));
+    }
+
+    public synchronized int getIndexForApp(String packageName) {
+        return findSlotForPrefix(PREFIX_PACKAGE_NAME, packageName);
+    }
+
+    public synchronized int getIndexForOrigin(String origin) {
+        return findSlotForPrefix(PREFIX_ORIGIN, origin);
+    }
+
+    protected int findSlotForPrefix(String prefix, String value) {
+        for (int i = 0; i < MAX_WEB_APPS; ++i) {
+            if (mPrefs.getString(prefix + i, "").equals(value)) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    public synchronized String getAppForIndex(int index) {
+        return mPrefs.getString(appKey(index), null);
+    }
+
+    public synchronized int releaseIndexForApp(String app) {
+        int index = getIndexForApp(app);
+        if (index == -1)
+            return -1;
+
+        releaseIndex(index);
+        return index;
+    }
+
+    public synchronized void releaseIndex(final int index) {
+        save(mPrefs.edit().remove(appKey(index)).remove(iconKey(index)).remove(originKey(index)));
+    }
+
+    public void putOrigin(int index, String origin) {
+        save(mPrefs.edit().putString(originKey(index), origin));
+    }
+
+    public String getOrigin(int index) {
+        return mPrefs.getString(originKey(index), null);
+    }
+
+    public int getColor(int index) {
+        return mPrefs.getInt(iconKey(index), -1);
+    }
+
+    /**
+     * Migrate old prefs to their new equivalents if this app was originally
+     * installed by the shortcut-based implementation.
+     */
+    public void maybeMigrateOldPrefs(int index) {
+        if (!mPrefs.contains(oldAppKey(index))) {
+            return;
+        }
+
+        Log.i(LOGTAG, "migrating old prefs");
+
+        // The old appKey pref stored the origin, while the new appKey pref
+        // stores the packageName, so we migrate oldAppKey to the origin pref.
+        putOrigin(index, mPrefs.getString(oldAppKey(index), null));
+
+        // The old iconKey pref actually stored the splash screen background
+        // color, so we migrate oldIconKey to the color pref.
+        updateColor(index, mPrefs.getInt(oldIconKey(index), -1));
+
+        // Remove the old prefs so we don't migrate them the next time around.
+        save(mPrefs.edit().remove(oldAppKey(index)).remove(oldIconKey(index)));
+    }
+}