diff -r 000000000000 -r 6474c204b198 browser/components/migration/src/FirefoxProfileMigrator.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/migration/src/FirefoxProfileMigrator.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,134 @@
+/* -*- Mode: js; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 et */
+ /* 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/. */
+
+"use strict";
+
+/*
+ * Migrates from a Firefox profile in a lossy manner in order to clean up a
+ * user's profile.  Data is only migrated where the benefits outweigh the
+ * potential problems caused by importing undesired/invalid configurations
+ * from the source profile.
+ */
+
+Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
+Components.utils.import("resource:///modules/MigrationUtils.jsm");
+Components.utils.import("resource://gre/modules/Services.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "PlacesBackups",
+                                  "resource://gre/modules/PlacesBackups.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "SessionMigration",
+                                  "resource:///modules/sessionstore/SessionMigration.jsm");
+
+function FirefoxProfileMigrator() { }
+
+FirefoxProfileMigrator.prototype = Object.create(MigratorPrototype);
+
+FirefoxProfileMigrator.prototype._getFileObject = function(dir, fileName) {
+  let file = dir.clone();
+  file.append(fileName);
+
+  // File resources are monolithic.  We don't make partial copies since
+  // they are not expected to work alone. Return null to avoid trying to
+  // copy non-existing files.
+  return file.exists() ? file : null;
+}
+
+FirefoxProfileMigrator.prototype.getResources = function() {
+  // Only allow migrating from the default (selected) profile since this will
+  // be the only one returned by the toolkit profile service after bug 214675.
+  let sourceProfile =
+    Components.classes["@mozilla.org/toolkit/profile-service;1"]
+              .getService(Components.interfaces.nsIToolkitProfileService)
+              .selectedProfile;
+  if (!sourceProfile)
+    return null;
+
+  let sourceProfileDir = sourceProfile.rootDir;
+  if (!sourceProfileDir || !sourceProfileDir.exists() ||
+      !sourceProfileDir.isReadable())
+    return null;
+
+  // Being a startup-only migrator, we can rely on
+  // MigrationUtils.profileStartup being set.
+  let currentProfileDir = MigrationUtils.profileStartup.directory;
+
+  // Surely data cannot be imported from the current profile.
+  if (sourceProfileDir.equals(currentProfileDir))
+    return null;
+
+  let getFileResource = function(aMigrationType, aFileNames) {
+    let files = [];
+    for (let fileName of aFileNames) {
+      let file = this._getFileObject(sourceProfileDir, fileName);
+      if (!file)
+        return null;
+      files.push(file);
+    }
+    return {
+      type: aMigrationType,
+      migrate: function(aCallback) {
+        for (let file of files) {
+          file.copyTo(currentProfileDir, "");
+        }
+        aCallback(true);
+      }
+    };
+  }.bind(this);
+
+  let types = MigrationUtils.resourceTypes;
+  let places = getFileResource(types.HISTORY, ["places.sqlite"]);
+  let cookies = getFileResource(types.COOKIES, ["cookies.sqlite"]);
+  let passwords = getFileResource(types.PASSWORDS,
+                                  ["signons.sqlite", "key3.db"]);
+  let formData = getFileResource(types.FORMDATA, ["formhistory.sqlite"]);
+  let bookmarksBackups = getFileResource(types.OTHERDATA,
+    [PlacesBackups.profileRelativeFolderPath]);
+  let dictionary = getFileResource(types.OTHERDATA, ["persdict.dat"]);
+
+  let sessionFile = this._getFileObject(sourceProfileDir, "sessionstore.js");
+  let session;
+  if (sessionFile) {
+    session = {
+      type: types.SESSION,
+      migrate: function(aCallback) {
+        let newSessionFile = currentProfileDir.clone();
+        newSessionFile.append("sessionstore.js");
+        let migrationPromise = SessionMigration.migrate(sessionFile.path, newSessionFile.path);
+        migrationPromise.then(function() {
+          let buildID = Services.appinfo.platformBuildID;
+          let mstone = Services.appinfo.platformVersion;
+          // Force the browser to one-off resume the session that we give it:
+          Services.prefs.setBoolPref("browser.sessionstore.resume_session_once", true);
+          // Reset the homepage_override prefs so that the browser doesn't override our
+          // session with the "what's new" page:
+          Services.prefs.setCharPref("browser.startup.homepage_override.mstone", mstone);
+          Services.prefs.setCharPref("browser.startup.homepage_override.buildID", buildID);
+          // It's too early in startup for the pref service to have a profile directory,
+          // so we have to manually tell it where to save the prefs file.
+          let newPrefsFile = currentProfileDir.clone();
+          newPrefsFile.append("prefs.js");
+          Services.prefs.savePrefFile(newPrefsFile);
+          aCallback(true);
+        }, function() {
+          aCallback(false);
+        });
+      }
+    }
+  }
+
+  return [r for each (r in [places, cookies, passwords, formData,
+                            dictionary, bookmarksBackups, session]) if (r)];
+}
+
+Object.defineProperty(FirefoxProfileMigrator.prototype, "startupOnlyMigrator", {
+  get: function() true
+});
+
+
+FirefoxProfileMigrator.prototype.classDescription = "Firefox Profile Migrator";
+FirefoxProfileMigrator.prototype.contractID = "@mozilla.org/profile/migrator;1?app=browser&type=firefox";
+FirefoxProfileMigrator.prototype.classID = Components.ID("{91185366-ba97-4438-acba-48deaca63386}");
+
+this.NSGetFactory = XPCOMUtils.generateNSGetFactory([FirefoxProfileMigrator]);