diff -r 000000000000 -r 6474c204b198 mobile/android/base/db/SharedBrowserDatabaseProvider.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mobile/android/base/db/SharedBrowserDatabaseProvider.java	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,115 @@
+/* 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.db;
+
+import org.mozilla.gecko.db.BrowserContract.CommonColumns;
+import org.mozilla.gecko.db.BrowserContract.SyncColumns;
+import org.mozilla.gecko.db.PerProfileDatabases.DatabaseHelperFactory;
+
+import android.content.Context;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import android.net.Uri;
+import android.util.Log;
+
+/**
+ * A ContentProvider subclass that provides per-profile browser.db access
+ * that can be safely shared between multiple providers.
+ *
+ * If multiple ContentProvider classes wish to share a database, it's
+ * vitally important that they use the same SQLiteOpenHelpers for access.
+ *
+ * Failure to do so can cause accidental concurrent writes, with the result
+ * being unexpected SQLITE_BUSY errors.
+ *
+ * This class provides a static {@link PerProfileDatabases} instance, lazily
+ * initialized within {@link SharedBrowserDatabaseProvider#onCreate()}.
+ */
+public abstract class SharedBrowserDatabaseProvider extends AbstractPerProfileDatabaseProvider {
+    private static final String LOGTAG = SharedBrowserDatabaseProvider.class.getSimpleName();
+
+    private static PerProfileDatabases<BrowserDatabaseHelper> databases;
+
+    @Override
+    protected PerProfileDatabases<BrowserDatabaseHelper> getDatabases() {
+        return databases;
+    }
+
+    @Override
+    public boolean onCreate() {
+        // If necessary, do the shared DB work.
+        synchronized (SharedBrowserDatabaseProvider.class) {
+            if (databases != null) {
+                return true;
+            }
+
+            final DatabaseHelperFactory<BrowserDatabaseHelper> helperFactory = new DatabaseHelperFactory<BrowserDatabaseHelper>() {
+                @Override
+                public BrowserDatabaseHelper makeDatabaseHelper(Context context, String databasePath) {
+                    return new BrowserDatabaseHelper(context, databasePath);
+                }
+            };
+
+            databases = new PerProfileDatabases<BrowserDatabaseHelper>(getContext(), BrowserDatabaseHelper.DATABASE_NAME, helperFactory);
+        }
+
+        return true;
+    }
+
+    /**
+     * Clean up some deleted records from the specified table.
+     *
+     * If called in an existing transaction, it is the caller's responsibility
+     * to ensure that the transaction is already upgraded to a writer, because
+     * this method issues a read followed by a write, and thus is potentially
+     * vulnerable to an unhandled SQLITE_BUSY failure during the upgrade.
+     *
+     * If not called in an existing transaction, no new explicit transaction
+     * will be begun.
+     */
+    protected void cleanUpSomeDeletedRecords(Uri fromUri, String tableName) {
+        Log.d(LOGTAG, "Cleaning up deleted records from " + tableName);
+
+        // We clean up records marked as deleted that are older than a
+        // predefined max age. It's important not be too greedy here and
+        // remove only a few old deleted records at a time.
+
+        // we cleanup records marked as deleted that are older than a
+        // predefined max age. It's important not be too greedy here and
+        // remove only a few old deleted records at a time.
+
+        // Maximum age of deleted records to be cleaned up (20 days in ms)
+        final long MAX_AGE_OF_DELETED_RECORDS = 86400000 * 20;
+
+        // Number of records marked as deleted to be removed
+        final long DELETED_RECORDS_PURGE_LIMIT = 5;
+
+        // Android SQLite doesn't have LIMIT on DELETE. Instead, query for the
+        // IDs of matching rows, then delete them in one go.
+        final long now = System.currentTimeMillis();
+        final String selection = SyncColumns.IS_DELETED + " = 1 AND " +
+                SyncColumns.DATE_MODIFIED + " <= " +
+                (now - MAX_AGE_OF_DELETED_RECORDS);
+
+        final String profile = fromUri.getQueryParameter(BrowserContract.PARAM_PROFILE);
+        final SQLiteDatabase db = getWritableDatabaseForProfile(profile, isTest(fromUri));
+        final String[] ids;
+        final String limit = Long.toString(DELETED_RECORDS_PURGE_LIMIT, 10);
+        final Cursor cursor = db.query(tableName, new String[] { CommonColumns._ID }, selection, null, null, null, null, limit);
+        try {
+            ids = new String[cursor.getCount()];
+            int i = 0;
+            while (cursor.moveToNext()) {
+                ids[i++] = Long.toString(cursor.getLong(0), 10);
+            }
+        } finally {
+            cursor.close();
+        }
+
+        final String inClause = computeSQLInClause(ids.length,
+                CommonColumns._ID);
+        db.delete(tableName, inClause, ids);
+    }
+}