--- a/toolkit/xre/nsXREDirProvider.cpp
+++ b/toolkit/xre/nsXREDirProvider.cpp
@@ -534,20 +534,16 @@ nsXREDirProvider::GetFile(const char* aP
         rv = file->AppendNative(NS_LITERAL_CSTRING("localstore-safe.rdf"));
         file->Remove(false);
       }
       else {
         rv = file->AppendNative(NS_LITERAL_CSTRING("localstore.rdf"));
         ensureFilePermissions = true;
       }
     }
-    else if (!strcmp(aProperty, NS_APP_USER_MIMETYPES_50_FILE)) {
-      rv = file->AppendNative(NS_LITERAL_CSTRING("mimeTypes.rdf"));
-      ensureFilePermissions = true;
-    }
     else if (!strcmp(aProperty, NS_APP_DOWNLOADS_50_FILE)) {
       rv = file->AppendNative(NS_LITERAL_CSTRING("downloads.rdf"));
     }
     else if (!strcmp(aProperty, NS_APP_PREFS_OVERRIDE_DIR)) {
       rv = mProfileDir->Clone(getter_AddRefs(file));
       nsresult tmp = file->AppendNative(NS_LITERAL_CSTRING(PREF_OVERRIDE_DIRNAME));
       if (NS_FAILED(tmp)) {
         rv = tmp;

--- a/uriloader/exthandler/nsHandlerService.js
+++ b/uriloader/exthandler/nsHandlerService.js
@@ -923,17 +923,18 @@ HandlerService.prototype = {
                               getService(Ci.nsIRDFContainerUtils);
     return this.__containerUtils;
   },
 
   // RDF datasource containing content handling config (i.e. mimeTypes.rdf)
   __ds: null,
   get _ds() {
     if (!this.__ds) {
-      var file = this._dirSvc.get("UMimTyp", Ci.nsIFile);
+      var file = this._dirSvc.get("ProfD", Ci.nsIFile);
+      file.append("mimeTypes.rdf");
       // FIXME: make this a memoizing getter if we use it anywhere else.
       var ioService = Cc["@mozilla.org/network/io-service;1"].
                       getService(Ci.nsIIOService);
       var fileHandler = ioService.getProtocolHandler("file").
                         QueryInterface(Ci.nsIFileProtocolHandler);
       this.__ds =
         this._rdf.GetDataSourceBlocking(fileHandler.getURLSpecFromFile(file));
       // do any necessary updating of the datastore

--- a/uriloader/exthandler/tests/unit/common_test_handlerService.js
+++ b/uriloader/exthandler/tests/unit/common_test_handlerService.js
@@ -4,34 +4,32 @@
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /**
  * This script is loaded by "test_handlerService_json.js" and "test_handlerService_rdf.js"
  * to make sure there is the same behavior when using two different implementations
  * of handlerService (JSON backend and RDF backend).
  */
 
-"use strict"
-
 Cu.import("resource://gre/modules/osfile.jsm");
 Cu.import("resource://gre/modules/Task.jsm");
 Cu.import("resource://testing-common/TestUtils.jsm");
 
 XPCOMUtils.defineLazyServiceGetter(this, "gMIMEService",
                                    "@mozilla.org/mime;1",
                                    "nsIMIMEService");
 XPCOMUtils.defineLazyServiceGetter(this, "gExternalProtocolService",
                                    "@mozilla.org/uriloader/external-protocol-service;1",
                                    "nsIExternalProtocolService");
 
 const pdfHandlerInfo = gMIMEService.getFromTypeAndExtension("application/pdf", null);
 const gzipHandlerInfo = gMIMEService.getFromTypeAndExtension("application/x-gzip", null);
 const ircHandlerInfo = gExternalProtocolService.getProtocolHandlerInfo("irc");
 
-let executable = HandlerServiceTest._dirSvc.get("TmpD", Ci.nsIFile);
+let executable = Services.dirsvc.get("TmpD", Ci.nsIFile);
 let localHandler = {
   name: "Local Handler",
   executable: executable,
   interfaces: [Ci.nsIHandlerApp, Ci.nsILocalHandlerApp, Ci.nsISupports],
   QueryInterface: function(iid) {
     if (!this.interfaces.some( function(v) { return iid.equals(v) } ))
       throw Cr.NS_ERROR_NO_INTERFACE;
     return this;

new file mode 100644
--- /dev/null
+++ b/uriloader/exthandler/tests/unit/head.js
@@ -0,0 +1,30 @@
+/* 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/. */
+
+/*
+ * Initialization for tests related to invoking external handler applications.
+ */
+
+"use strict";
+
+const { classes: Cc, interfaces: Ci, utils: Cu, results: Cr } = Components;
+
+Cu.import("resource://gre/modules/Services.jsm");
+
+do_get_profile();
+
+let rdfFile = Services.dirsvc.get("ProfD", Ci.nsIFile);
+rdfFile.append("mimeTypes.rdf")
+
+function deleteDatasourceFile() {
+  if (rdfFile.exists()) {
+    rdfFile.remove(false);
+  }
+}
+
+// Delete the existing datasource file, if any, so we start from scratch.
+// We also do this after finishing the tests, so there shouldn't be an old
+// file lying around, but just in case we delete it here as well.
+deleteDatasourceFile();
+do_register_cleanup(deleteDatasourceFile);

deleted file mode 100644
--- a/uriloader/exthandler/tests/unit/head_handlerService.js
+++ /dev/null
@@ -1,168 +0,0 @@
-/* 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/. */
-
-// Inspired by the Places infrastructure in head_bookmarks.js
-
-var Cc = Components.classes;
-var Ci = Components.interfaces;
-var Cr = Components.results;
-var Cu = Components.utils;
-
-var HandlerServiceTest = {
-  //**************************************************************************//
-  // Convenience Getters
-
-  __dirSvc: null,
-  get _dirSvc() {
-    if (!this.__dirSvc)
-      this.__dirSvc = Cc["@mozilla.org/file/directory_service;1"].
-                      getService(Ci.nsIProperties).
-                      QueryInterface(Ci.nsIDirectoryService);
-    return this.__dirSvc;
-  },
-
-  __consoleSvc: null,
-  get _consoleSvc() {
-    if (!this.__consoleSvc)
-      this.__consoleSvc = Cc["@mozilla.org/consoleservice;1"].
-                          getService(Ci.nsIConsoleService);
-    return this.__consoleSvc;
-  },
-
-
-  //**************************************************************************//
-  // nsISupports
-
-  interfaces: [Ci.nsIDirectoryServiceProvider, Ci.nsISupports],
-
-  QueryInterface: function HandlerServiceTest_QueryInterface(iid) {
-    if (!this.interfaces.some( function(v) { return iid.equals(v) } ))
-      throw Cr.NS_ERROR_NO_INTERFACE;
-    return this;
-  },
-
-
-  //**************************************************************************//
-  // Initialization & Destruction
-
-  init: function HandlerServiceTest_init() {
-    // Register ourselves as a directory provider for the datasource file
-    // if there isn't one registered already.
-    try {
-      this._dirSvc.get("UMimTyp", Ci.nsIFile);
-    } catch (ex) {
-      do_get_profile();
-      this._dirSvc.registerProvider(this);
-      this._providerRegistered = true;
-    }
-
-    // Delete the existing datasource file, if any, so we start from scratch.
-    // We also do this after finishing the tests, so there shouldn't be an old
-    // file lying around, but just in case we delete it here as well.
-    this._deleteDatasourceFile();
-
-    // Turn on logging so we can troubleshoot problems with the tests.
-    var prefBranch = Cc["@mozilla.org/preferences-service;1"].
-                     getService(Ci.nsIPrefBranch);
-    prefBranch.setBoolPref("browser.contentHandling.log", true);
-  },
-
-  destroy: function HandlerServiceTest_destroy() {
-    // Delete the existing datasource file, if any, so we don't leave test files
-    // lying around and we start from scratch the next time.
-    this._deleteDatasourceFile();
-    // Unregister the directory service provider
-    if (this._providerRegistered)
-      this._dirSvc.unregisterProvider(this);
-  },
-
-
-  //**************************************************************************//
-  // nsIDirectoryServiceProvider
-
-  getFile: function HandlerServiceTest_getFile(property, persistent) {
-    this.log("getFile: requesting " + property);
-
-    persistent.value = true;
-
-    if (property == "UMimTyp") {
-      var datasourceFile = this._dirSvc.get("ProfD", Ci.nsIFile);
-      datasourceFile.append("mimeTypes.rdf");
-      return datasourceFile;
-    }
-
-    // This causes extraneous errors to show up in the log when the directory
-    // service asks us first for CurProcD and MozBinD.  I wish there was a way
-    // to suppress those errors.
-    this.log("the following NS_ERROR_FAILURE exception in " +
-             "nsIDirectoryServiceProvider::getFile is expected, " +
-             "as we don't provide the '" + property + "' file");
-    throw Cr.NS_ERROR_FAILURE;
-  },
-
-
-  //**************************************************************************//
-  // Utilities
-
-  /**
-   * Delete the datasource file.
-   */
-  _deleteDatasourceFile: function HandlerServiceTest__deleteDatasourceFile() {
-    var file = this._dirSvc.get("UMimTyp", Ci.nsIFile);
-    if (file.exists())
-      file.remove(false);
-  },
-
-  /**
-   * Get the contents of the datasource as a serialized string.  Useful for
-   * debugging problems with test failures, i.e.:
-   *
-   * HandlerServiceTest.log(HandlerServiceTest.getDatasourceContents());
-   *
-   * @returns {string} the serialized datasource
-   */
-  getDatasourceContents: function HandlerServiceTest_getDatasourceContents() {
-    var rdf = Cc["@mozilla.org/rdf/rdf-service;1"].getService(Ci.nsIRDFService);
-
-    var ioService = Cc["@mozilla.org/network/io-service;1"].
-                    getService(Ci.nsIIOService);
-    var fileHandler = ioService.getProtocolHandler("file").
-                      QueryInterface(Ci.nsIFileProtocolHandler);
-    var fileURL = fileHandler.getURLSpecFromFile(this.getDatasourceFile());
-    var ds = rdf.GetDataSourceBlocking(fileURL);
-
-    var outputStream = {
-      data: "",
-      close: function() {},
-      flush: function() {},
-      write: function (buffer,count) {
-        this.data += buffer;
-        return count;
-      },
-      writeFrom: function (stream,count) {},
-      isNonBlocking: false
-    };
-
-    ds.QueryInterface(Components.interfaces.nsIRDFXMLSource);
-    ds.Serialize(outputStream);
-
-    return outputStream.data;
-  },
-
-  /**
-   * Log a message to the console and the test log.
-   */
-  log: function HandlerServiceTest_log(message) {
-    message = "*** HandlerServiceTest: " + message;
-    this._consoleSvc.logStringMessage(message);
-    print(message);
-  }
-
-};
-
-HandlerServiceTest.init();
-
-do_register_cleanup(function() {
-  HandlerServiceTest.destroy();
-});

--- a/uriloader/exthandler/tests/unit/test_handlerService.js
+++ b/uriloader/exthandler/tests/unit/test_handlerService.js
@@ -59,17 +59,17 @@ function run_test() {
   //**************************************************************************//
   // Sample Data
 
   // It doesn't matter whether or not this nsIFile is actually executable,
   // only that it has a path and exists.  Since we don't know any executable
   // that exists on all platforms (except possibly the application being
   // tested, but there doesn't seem to be a way to get a reference to that
   // from the directory service), we use the temporary directory itself.
-  var executable = HandlerServiceTest._dirSvc.get("TmpD", Ci.nsIFile);
+  var executable = Services.dirsvc.get("TmpD", Ci.nsIFile);
   // XXX We could, of course, create an actual executable in the directory:
   //executable.append("localhandler");
   //if (!executable.exists())
   //  executable.create(Ci.nsIFile.NORMAL_FILE_TYPE, 0o755);
 
   var localHandler = {
     name: "Local Handler",
     executable: executable,
@@ -433,17 +433,16 @@ function run_test() {
   lolHandler.alwaysAskBeforeHandling = false;
 
   // store the handler
   do_check_false(handlerSvc.exists(lolHandler));
   handlerSvc.store(lolHandler);
   do_check_true(handlerSvc.exists(lolHandler));
 
   // Get a file:// string pointing to mimeTypes.rdf
-  var rdfFile = HandlerServiceTest._dirSvc.get("UMimTyp", Ci.nsIFile);
   var fileHandler = ioService.getProtocolHandler("file").QueryInterface(Ci.nsIFileProtocolHandler);
   var rdfFileURI = fileHandler.getURLSpecFromFile(rdfFile);
 
   // Assign a file extenstion to the handler. handlerSvc.store() doesn't
   // actually store any file extensions added with setFileExtensions(), you
   // have to wade into RDF muck to do so.
 
   // Based on toolkit/mozapps/downloads/content/helperApps.js :: addExtension()

--- a/uriloader/exthandler/tests/unit/test_handlerService_json.js
+++ b/uriloader/exthandler/tests/unit/test_handlerService_json.js
@@ -2,19 +2,16 @@
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /**
  * Tests the handlerService interfaces using JSON backend.
  */
 
-"use strict"
-
-
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
 Cu.import("resource://gre/modules/NetUtil.jsm");
 
 XPCOMUtils.defineLazyServiceGetter(this, "gHandlerService",
                                    "@mozilla.org/uriloader/handler-service-json;1",
                                    "nsIHandlerService");
 

--- a/uriloader/exthandler/tests/unit/test_handlerService_rdf.js
+++ b/uriloader/exthandler/tests/unit/test_handlerService_rdf.js
@@ -2,42 +2,37 @@
 /* vim: set ts=2 et sw=2 tw=80: */
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
 /**
  * Tests the handlerService interfaces using RDF backend.
  */
 
-"use strict"
-
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
 Cu.import("resource://gre/modules/NetUtil.jsm");
 
 XPCOMUtils.defineLazyServiceGetter(this, "gHandlerService",
                                    "@mozilla.org/uriloader/handler-service;1",
                                    "nsIHandlerService");
 
 var scriptFile = do_get_file("common_test_handlerService.js");
 Services.scriptloader.loadSubScript(NetUtil.newURI(scriptFile).spec);
 
 var prepareImportDB = Task.async(function* () {
   yield reloadData();
 
-  let dst = HandlerServiceTest._dirSvc.get("UMimTyp", Ci.nsIFile);
-  yield OS.File.copy(do_get_file("mimeTypes.rdf").path, dst.path);
-  Assert.ok((yield OS.File.exists(dst.path)), "should have a DB now");
+  yield OS.File.copy(do_get_file("mimeTypes.rdf").path, rdfFile.path);
 });
 
 var removeImportDB = Task.async(function* () {
   yield reloadData();
-  HandlerServiceTest._deleteDatasourceFile();
-  let dst = HandlerServiceTest._dirSvc.get("UMimTyp", Ci.nsIFile);
-  Assert.ok(!(yield OS.File.exists(dst.path)), "should not have a DB now");
+
+  yield OS.File.remove(rdfFile.path, { ignoreAbsent: true });
 });
 
 var reloadData = Task.async(function* () {
   // Force the initialization of handlerService to prevent observer is not initialized yet.
   let svc = gHandlerService;
   let promise = TestUtils.topicObserved("handlersvc-rdf-replace-complete");
   Services.obs.notifyObservers(null, "handlersvc-rdf-replace", null);
   yield promise;

--- a/uriloader/exthandler/tests/unit/test_punycodeURIs.js
+++ b/uriloader/exthandler/tests/unit/test_punycodeURIs.js
@@ -97,17 +97,17 @@ function run_test() {
   // Set an environment variable for WriteArgument to pick up
   var envSvc =
     Components.classes["@mozilla.org/process/environment;1"]
               .getService(Components.interfaces.nsIEnvironment);
 
   // The Write Argument file needs to know where its libraries are, so
   // just force the path variable
   // For mac
-  var greDir = HandlerServiceTest._dirSvc.get("GreD", Components.interfaces.nsIFile);
+  var greDir = Services.dirsvc.get("GreD", Components.interfaces.nsIFile);
 
   envSvc.set("DYLD_LIBRARY_PATH", greDir.path);
   // For Linux
   envSvc.set("LD_LIBRARY_PATH", greDir.path);
   //XXX: handle windows
 
   // Now tell it where we want the file.
   envSvc.set("WRITE_ARGUMENT_FILE", outFile.path);

--- a/uriloader/exthandler/tests/unit/xpcshell.ini
+++ b/uriloader/exthandler/tests/unit/xpcshell.ini
@@ -1,10 +1,10 @@
 [DEFAULT]
-head = head_handlerService.js
+head = head.js
 run-sequentially = Bug 912235 - Intermittent failures
 firefox-appdir = browser
 support-files = common_test_handlerService.js
 
 [test_getTypeFromExtension_ext_to_type_mapping.js]
 [test_getTypeFromExtension_with_empty_Content_Type.js]
 [test_badMIMEType.js]
 [test_handlerService.js]

--- a/xpcom/io/nsAppDirectoryServiceDefs.h
+++ b/xpcom/io/nsAppDirectoryServiceDefs.h
@@ -66,17 +66,16 @@
 #define NS_APP_USER_PROFILE_50_DIR              "ProfD"
 #define NS_APP_USER_PROFILE_LOCAL_50_DIR        "ProfLD"
 
 #define NS_APP_USER_CHROME_DIR                  "UChrm"
 #define NS_APP_USER_SEARCH_DIR                  "UsrSrchPlugns"
 
 #define NS_APP_LOCALSTORE_50_FILE               "LclSt"
 #define NS_APP_USER_PANELS_50_FILE              "UPnls"
-#define NS_APP_USER_MIMETYPES_50_FILE           "UMimTyp"
 #define NS_APP_CACHE_PARENT_DIR                 "cachePDir"
 
 #define NS_APP_DOWNLOADS_50_FILE                "DLoads"
 
 #define NS_APP_SEARCH_50_FILE                   "SrchF"
 
 #define NS_APP_INSTALL_CLEANUP_DIR              "XPIClnupD"  //location of xpicleanup.dat xpicleanup.exe