diff --git a/modules/libpref/src/Makefile.in b/modules/libpref/Makefile.in
similarity index 100%
rename from modules/libpref/src/Makefile.in
rename to modules/libpref/Makefile.in
diff --git a/modules/libpref/src/Preferences.cpp b/modules/libpref/Preferences.cpp
similarity index 100%
rename from modules/libpref/src/Preferences.cpp
rename to modules/libpref/Preferences.cpp
diff --git a/modules/libpref/public/Preferences.h b/modules/libpref/Preferences.h
similarity index 100%
rename from modules/libpref/public/Preferences.h
rename to modules/libpref/Preferences.h
diff --git a/modules/libpref/src/init/all.js b/modules/libpref/init/all.js
similarity index 100%
rename from modules/libpref/src/init/all.js
rename to modules/libpref/init/all.js
diff --git a/modules/libpref/moz.build b/modules/libpref/moz.build
index 47e64e62391..4f9a562a20c 100644
--- a/modules/libpref/moz.build
+++ b/modules/libpref/moz.build
@@ -4,6 +4,40 @@
 # 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/.
 
-DIRS += ['public', 'src']
 TEST_DIRS += ['test']
 
+XPIDL_SOURCES += [
+    'nsIPrefBranch.idl',
+    'nsIPrefBranch2.idl',
+    'nsIPrefBranchInternal.idl',
+    'nsIPrefLocalizedString.idl',
+    'nsIPrefService.idl',
+    'nsIRelativeFilePref.idl',
+]
+
+XPIDL_MODULE = 'pref'
+
+EXPORTS.mozilla += [
+    'Preferences.h',
+]
+
+UNIFIED_SOURCES += [
+    'nsPrefBranch.cpp',
+    'nsPrefsFactory.cpp',
+    'Preferences.cpp',
+    'prefread.cpp',
+]
+
+# prefapi.cpp cannot be built in unified mode because it uses plarena.h
+SOURCES += [
+    'prefapi.cpp',
+]
+
+MSVC_ENABLE_PGO = True
+
+include('/ipc/chromium/chromium-config.mozbuild')
+
+FINAL_LIBRARY = 'xul'
+
+DEFINES['OS_ARCH'] = CONFIG['OS_ARCH']
+DEFINES['MOZ_WIDGET_TOOLKIT'] = CONFIG['MOZ_WIDGET_TOOLKIT']
diff --git a/modules/libpref/public/nsIPrefBranch.idl b/modules/libpref/nsIPrefBranch.idl
similarity index 100%
rename from modules/libpref/public/nsIPrefBranch.idl
rename to modules/libpref/nsIPrefBranch.idl
diff --git a/modules/libpref/public/nsIPrefBranch2.idl b/modules/libpref/nsIPrefBranch2.idl
similarity index 100%
rename from modules/libpref/public/nsIPrefBranch2.idl
rename to modules/libpref/nsIPrefBranch2.idl
diff --git a/modules/libpref/public/nsIPrefBranchInternal.idl b/modules/libpref/nsIPrefBranchInternal.idl
similarity index 100%
rename from modules/libpref/public/nsIPrefBranchInternal.idl
rename to modules/libpref/nsIPrefBranchInternal.idl
diff --git a/modules/libpref/public/nsIPrefLocalizedString.idl b/modules/libpref/nsIPrefLocalizedString.idl
similarity index 100%
rename from modules/libpref/public/nsIPrefLocalizedString.idl
rename to modules/libpref/nsIPrefLocalizedString.idl
diff --git a/modules/libpref/public/nsIPrefService.idl b/modules/libpref/nsIPrefService.idl
similarity index 100%
rename from modules/libpref/public/nsIPrefService.idl
rename to modules/libpref/nsIPrefService.idl
diff --git a/modules/libpref/public/nsIRelativeFilePref.idl b/modules/libpref/nsIRelativeFilePref.idl
similarity index 100%
rename from modules/libpref/public/nsIRelativeFilePref.idl
rename to modules/libpref/nsIRelativeFilePref.idl
diff --git a/modules/libpref/src/nsPrefBranch.cpp b/modules/libpref/nsPrefBranch.cpp
similarity index 100%
rename from modules/libpref/src/nsPrefBranch.cpp
rename to modules/libpref/nsPrefBranch.cpp
diff --git a/modules/libpref/src/nsPrefBranch.h b/modules/libpref/nsPrefBranch.h
similarity index 100%
rename from modules/libpref/src/nsPrefBranch.h
rename to modules/libpref/nsPrefBranch.h
diff --git a/modules/libpref/src/nsPrefsFactory.cpp b/modules/libpref/nsPrefsFactory.cpp
similarity index 100%
rename from modules/libpref/src/nsPrefsFactory.cpp
rename to modules/libpref/nsPrefsFactory.cpp
diff --git a/modules/libpref/src/prefapi.cpp b/modules/libpref/prefapi.cpp
similarity index 100%
rename from modules/libpref/src/prefapi.cpp
rename to modules/libpref/prefapi.cpp
diff --git a/modules/libpref/src/prefapi.h b/modules/libpref/prefapi.h
similarity index 100%
rename from modules/libpref/src/prefapi.h
rename to modules/libpref/prefapi.h
diff --git a/modules/libpref/src/prefapi_private_data.h b/modules/libpref/prefapi_private_data.h
similarity index 100%
rename from modules/libpref/src/prefapi_private_data.h
rename to modules/libpref/prefapi_private_data.h
diff --git a/modules/libpref/src/prefread.cpp b/modules/libpref/prefread.cpp
similarity index 100%
rename from modules/libpref/src/prefread.cpp
rename to modules/libpref/prefread.cpp
diff --git a/modules/libpref/src/prefread.h b/modules/libpref/prefread.h
similarity index 100%
rename from modules/libpref/src/prefread.h
rename to modules/libpref/prefread.h
diff --git a/modules/libpref/public/moz.build b/modules/libpref/public/moz.build
deleted file mode 100644
index 0ba94350165..00000000000
--- a/modules/libpref/public/moz.build
+++ /dev/null
@@ -1,21 +0,0 @@
-# -*- Mode: python; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40 -*-
-# vim: set filetype=python:
-# 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/.
-
-XPIDL_SOURCES += [
-    'nsIPrefBranch.idl',
-    'nsIPrefBranch2.idl',
-    'nsIPrefBranchInternal.idl',
-    'nsIPrefLocalizedString.idl',
-    'nsIPrefService.idl',
-    'nsIRelativeFilePref.idl',
-]
-
-XPIDL_MODULE = 'pref'
-
-EXPORTS.mozilla += [
-    'Preferences.h',
-]
-
diff --git a/modules/libpref/src/moz.build b/modules/libpref/src/moz.build
deleted file mode 100644
index f863f76d9cb..00000000000
--- a/modules/libpref/src/moz.build
+++ /dev/null
@@ -1,26 +0,0 @@
-# -*- Mode: python; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40 -*-
-# vim: set filetype=python:
-# 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/.
-
-UNIFIED_SOURCES += [
-    'nsPrefBranch.cpp',
-    'nsPrefsFactory.cpp',
-    'Preferences.cpp',
-    'prefread.cpp',
-]
-
-# prefapi.cpp cannot be built in unified mode because it uses plarena.h
-SOURCES += [
-    'prefapi.cpp',
-]
-
-MSVC_ENABLE_PGO = True
-
-include('/ipc/chromium/chromium-config.mozbuild')
-
-FINAL_LIBRARY = 'xul'
-
-DEFINES['OS_ARCH'] = CONFIG['OS_ARCH']
-DEFINES['MOZ_WIDGET_TOOLKIT'] = CONFIG['MOZ_WIDGET_TOOLKIT']