--- a/config/recurse.mk
+++ b/config/recurse.mk
@@ -166,16 +166,19 @@ js/xpconnect/src/export: dom/bindings/ex
 accessible/xpcom/export: xpcom/xpidl/export
 
 # The widget binding generator code is part of the annotationProcessors.
 widget/android/bindings/export: build/annotationProcessors/export
 
 # .xpt generation needs the xpidl lex/yacc files
 xpcom/xpidl/export: xpcom/idl-parser/xpidl/export
 
+# CSS2Properties.webidl needs ServoCSSPropList.py from layout/style
+dom/bindings/export: layout/style/export
+
 ifdef ENABLE_CLANG_PLUGIN
 $(filter-out config/host build/unix/stdc++compat/% build/clang-plugin/%,$(compile_targets)): build/clang-plugin/target build/clang-plugin/tests/target
 build/clang-plugin/tests/target: build/clang-plugin/target
 endif
 
 # Interdependencies that moz.build world don't know about yet for compilation.
 # Note some others are hardcoded or "guessed" in recursivemake.py and emitter.py
 ifeq ($(MOZ_WIDGET_TOOLKIT),gtk3)

--- a/devtools/shared/css/generated/mach_commands.py
+++ b/devtools/shared/css/generated/mach_commands.py
@@ -45,42 +45,27 @@ class MachCommands(MachCommandBase):
 
         self.output_template({
             'preferences': stringify(preferences),
             'cssProperties': stringify(db['cssProperties']),
             'pseudoElements': stringify(db['pseudoElements'])})
 
     def get_preferences(self):
         """Get all of the preferences associated with enabling and disabling a property."""
-        # Build the command to run the preprocessor on PythonCSSProps.h
-        headerPath = resolve_path(self.topsrcdir, 'layout/style/PythonCSSProps.h')
-
-        cpp = self.substs['CPP']
-
-        if not cpp:
-            print("Unable to find the cpp program. Please do a full, nonartifact")
-            print("build and try this again.")
-            sys.exit(1)
-
-        if type(cpp) is list:
-            cmd = cpp
-        else:
-            cmd = shellutil.split(cpp)
-        cmd += shellutil.split(self.substs['ACDEFINES'])
-        cmd.append(headerPath)
-
-        # The preprocessed list takes the following form:
+        # The data takes the following form:
         # [ (name, prop, id, flags, pref, proptype), ... ]
-        preprocessed = eval(subprocess.check_output(cmd))
+        dataPath = resolve_path(self.topobjdir, 'layout/style/ServoCSSPropList.py')
+        with open(dataPath, "r") as f:
+            data = eval(f.read())
 
         # Map this list
         # (name, prop, id, flags, pref, proptype) => (name, pref)
         preferences = [
             (name, pref)
-            for name, prop, id, flags, pref, proptype in preprocessed
+            for name, prop, id, flags, pref, proptype in data
             if 'CSS_PROPERTY_INTERNAL' not in flags and pref]
 
         return preferences
 
     def get_properties_db_from_xpcshell(self):
         """Generate the static css properties db for devtools from an xpcshell script."""
         build = MozbuildObject.from_environment()
 

--- a/devtools/shared/css/generated/properties-db.js
+++ b/devtools/shared/css/generated/properties-db.js
@@ -9475,20 +9475,16 @@ exports.PSEUDO_ELEMENTS = [
 ];
 
 /**
  * A list of the preferences keys for whether a CSS property is enabled or not. This is
  * exposed for testing purposes.
  */
 exports.PREFERENCES = [
   [
-    "all",
-    "layout.css.all-shorthand.enabled"
-  ],
-  [
     "background-blend-mode",
     "layout.css.background-blend-mode.enabled"
   ],
   [
     "box-decoration-break",
     "layout.css.box-decoration-break.enabled"
   ],
   [
@@ -9527,32 +9523,24 @@ exports.PREFERENCES = [
     "mix-blend-mode",
     "layout.css.mix-blend-mode.enabled"
   ],
   [
     "-moz-osx-font-smoothing",
     "layout.css.osx-font-smoothing.enabled"
   ],
   [
-    "overflow-clip-box",
-    "layout.css.overflow-clip-box.enabled"
-  ],
-  [
     "overflow-clip-box-block",
     "layout.css.overflow-clip-box.enabled"
   ],
   [
     "overflow-clip-box-inline",
     "layout.css.overflow-clip-box.enabled"
   ],
   [
-    "overscroll-behavior",
-    "layout.css.overscroll-behavior.enabled"
-  ],
-  [
     "overscroll-behavior-x",
     "layout.css.overscroll-behavior.enabled"
   ],
   [
     "overscroll-behavior-y",
     "layout.css.overscroll-behavior.enabled"
   ],
   [
@@ -9579,20 +9567,16 @@ exports.PREFERENCES = [
     "scroll-snap-points-x",
     "layout.css.scroll-snap.enabled"
   ],
   [
     "scroll-snap-points-y",
     "layout.css.scroll-snap.enabled"
   ],
   [
-    "scroll-snap-type",
-    "layout.css.scroll-snap.enabled"
-  ],
-  [
     "scroll-snap-type-x",
     "layout.css.scroll-snap.enabled"
   ],
   [
     "scroll-snap-type-y",
     "layout.css.scroll-snap.enabled"
   ],
   [
@@ -9611,20 +9595,16 @@ exports.PREFERENCES = [
     "-webkit-text-fill-color",
     "layout.css.prefixes.webkit"
   ],
   [
     "text-justify",
     "layout.css.text-justify.enabled"
   ],
   [
-    "-webkit-text-stroke",
-    "layout.css.prefixes.webkit"
-  ],
-  [
     "-webkit-text-stroke-color",
     "layout.css.prefixes.webkit"
   ],
   [
     "-webkit-text-stroke-width",
     "layout.css.prefixes.webkit"
   ],
   [
@@ -9635,16 +9615,36 @@ exports.PREFERENCES = [
     "transform-box",
     "svg.transform-box.enabled"
   ],
   [
     "translate",
     "layout.css.individual-transform.enabled"
   ],
   [
+    "all",
+    "layout.css.all-shorthand.enabled"
+  ],
+  [
+    "overflow-clip-box",
+    "layout.css.overflow-clip-box.enabled"
+  ],
+  [
+    "overscroll-behavior",
+    "layout.css.overscroll-behavior.enabled"
+  ],
+  [
+    "scroll-snap-type",
+    "layout.css.scroll-snap.enabled"
+  ],
+  [
+    "-webkit-text-stroke",
+    "layout.css.prefixes.webkit"
+  ],
+  [
     "-moz-animation",
     "layout.css.prefixes.animations"
   ],
   [
     "-moz-animation-delay",
     "layout.css.prefixes.animations"
   ],
   [

--- a/dom/bindings/GenerateCSS2PropertiesWebIDL.py
+++ b/dom/bindings/GenerateCSS2PropertiesWebIDL.py
@@ -1,34 +1,27 @@
 # 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/.
 
 import sys
 import string
 import argparse
-import subprocess
-import buildconfig
-from mozbuild import shellutil
 
 # Generates a line of WebIDL with the given spelling of the property name
 # (whether camelCase, _underscorePrefixed, etc.) and the given array of
 # extended attributes.
 def generateLine(propName, extendedAttrs):
     return "  [%s] attribute DOMString %s;\n" % (", ".join(extendedAttrs),
                                                  propName)
-def generate(output, idlFilename, preprocessorHeader):
-    cpp = list(buildconfig.substs['CPP'])
-    cpp += shellutil.split(buildconfig.substs['ACDEFINES'])
-    cpp.append(preprocessorHeader)
-    preprocessed = subprocess.check_output(cpp)
-
-    propList = eval(preprocessed)
+def generate(output, idlFilename, dataFile):
+    with open(dataFile, "r") as f:
+        propList = eval(f.read())
     props = ""
-    for [name, prop, id, flags, pref, proptype] in propList:
+    for name, prop, id, flags, pref, proptype in propList:
         if "CSS_PROPERTY_INTERNAL" in flags:
             continue
         # Unfortunately, even some of the getters here are fallible
         # (e.g. on nsComputedDOMStyle).
         extendedAttrs = ["CEReactions", "Throws", "TreatNullAs=EmptyString",
                          "SetterNeedsSubjectPrincipal=NonSystem"]
         if pref is not "":
             extendedAttrs.append('Pref="%s"' % pref)

--- a/dom/bindings/Makefile.in
+++ b/dom/bindings/Makefile.in
@@ -10,29 +10,16 @@ ifdef COMPILE_ENVIRONMENT
 include webidlsrcs.mk
 
 # These come from webidlsrcs.mk.
 # TODO Write directly into backend.mk (bug 1281618)
 CPPSRCS += $(globalgen_sources) $(unified_binding_cpp_files)
 
 include $(topsrcdir)/config/rules.mk
 
-# TODO This list should be emitted to a .pp file via
-# GenerateCSS2PropertiesWebIDL.py (bug 1281614)
-css2properties_dependencies = \
-  $(topsrcdir)/layout/style/nsCSSPropList.h \
-  $(topsrcdir)/layout/style/nsCSSPropAliasList.h \
-  $(webidl_base)/CSS2Properties.webidl.in \
-  $(topsrcdir)/layout/style/PythonCSSProps.h \
-  $(srcdir)/GenerateCSS2PropertiesWebIDL.py \
-  $(GLOBAL_DEPS) \
-  $(NULL)
-
-CSS2Properties.webidl: $(css2properties_dependencies)
-
 # Most of the logic for dependencies lives inside Python so it can be
 # used by multiple build backends. We simply have rules to generate
 # and include the .pp file.
 #
 # The generated .pp file contains all the important dependencies such as
 # changes to .webidl or .py files should result in code generation being
 # performed. But we do pull in file-lists.jon to catch file additions.
 codegen_dependencies := \

--- a/dom/bindings/moz.build
+++ b/dom/bindings/moz.build
@@ -174,10 +174,10 @@ if CONFIG['CC_TYPE'] in ('clang', 'gcc')
     ]
 
 if CONFIG['COMPILE_ENVIRONMENT']:
     GENERATED_FILES += ['CSS2Properties.webidl']
     css_props = GENERATED_FILES['CSS2Properties.webidl']
     css_props.script = 'GenerateCSS2PropertiesWebIDL.py:generate'
     css_props.inputs = [
         '/dom/webidl/CSS2Properties.webidl.in',
-        '/layout/style/PythonCSSProps.h',
+        '!/layout/style/ServoCSSPropList.py',
     ]

--- a/layout/style/GenerateCSSPropsGenerated.py
+++ b/layout/style/GenerateCSSPropsGenerated.py
@@ -1,27 +1,22 @@
 # 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/.
 
 import sys
 import string
 import argparse
-import subprocess
-import buildconfig
-from mozbuild import shellutil
 
-def get_properties(preprocessorHeader):
-    cpp = list(buildconfig.substs['CPP'])
-    cpp += shellutil.split(buildconfig.substs['ACDEFINES'])
-    cpp.append(preprocessorHeader)
-    preprocessed = subprocess.check_output(cpp)
+def get_properties(dataFile):
+    with open(dataFile, "r") as f:
+        properties = eval(f.read())
     properties = [{"name":p[0], "prop":p[1], "id":p[2],
                    "flags":p[3], "pref":p[4], "proptype":p[5]}
-                  for (i, p) in enumerate(eval(preprocessed))]
+                  for (i, p) in enumerate(properties)]
 
     # Sort the list so that longhand properties are intermingled first,
     # shorthand properties follow, then aliases appear last.
     # This matches the order of the nsCSSPropertyID enum.
 
     def property_compare(x, y):
         property_order = {"longhand": 0, "shorthand": 1, "alias": 2}
         return property_order[x["proptype"]] - property_order[y["proptype"]]
@@ -52,17 +47,17 @@ def generate_idl_names(properties):
             names.append("  nullptr,  // %s" % p["name"])
         else:
             names.append('  "%s",' % p["idlname"])
     return "\n".join(names)
 
 def generate_assertions(properties):
     def enum(p):
         if p["proptype"] is "alias":
-            return "eCSSPropertyAlias_%s" % p["id"]
+            return "eCSSPropertyAlias_%s" % p["id"][0]
         else:
             return "eCSSProperty_%s" % p["id"]
     msg = ('static_assert(%s == %d, "GenerateCSSPropsGenerated.py did not list '
            'properties in nsCSSPropertyID order");')
     return "\n".join(map(lambda p: msg % (enum(p), p["index"]), properties))
 
 def generate_idl_name_positions(properties):
     # Skip aliases.
@@ -74,22 +69,22 @@ def generate_idl_name_positions(properti
     # Annotate entries with the sorted position.
     ps = [(p, position) for position, p in enumerate(ps)]
 
     # Sort back to nsCSSPropertyID order.
     ps = sorted(ps, key=lambda (p, position): p["index"])
 
     return ",\n".join(map(lambda (p, position): "  %d" % position, ps))
 
-def generate(output, cppTemplate, preprocessorHeader):
+def generate(output, cppTemplate, dataFile):
     cppFile = open(cppTemplate, "r")
     cppTemplate = cppFile.read()
     cppFile.close()
 
-    properties = get_properties(preprocessorHeader)
+    properties = get_properties(dataFile)
     substitutions = {
         "idl_names": generate_idl_names(properties),
         "assertions": generate_assertions(properties),
         "idl_name_positions": generate_idl_name_positions(properties),
     }
     output.write("/* THIS IS AN AUTOGENERATED FILE.  DO NOT EDIT */\n\n" +
                  string.Template(cppTemplate).substitute(substitutions) + "\n")
 

deleted file mode 100644
--- a/layout/style/Makefile.in
+++ /dev/null
@@ -1,16 +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/.
-
-# TODO This list should be emitted to a .pp file via
-# GenerateCSSPropsGenerated.py (bug 1281614)
-csspropsidlnames_dependencies = \
-  $(srcdir)/nsCSSPropList.h \
-  $(srcdir)/nsCSSPropAliasList.h \
-  $(srcdir)/nsCSSPropsGenerated.inc.in \
-  $(srcdir)/PythonCSSProps.h \
-  $(srcdir)/GenerateCSSPropsGenerated.py \
-  $(GLOBAL_DEPS) \
-  $(NULL)
-
-nsCSSPropsGenerated.inc : $(csspropsidlnames_dependencies)

deleted file mode 100644
--- a/layout/style/PythonCSSProps.h
+++ /dev/null
@@ -1,42 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set ts=8 sts=2 et sw=2 tw=80: */
-/* 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/. */
-
-/* A file meant as input to the preprocessor only */
-
-/* DO_PROP serves as an extra level of indirection to allow expansion
-   of CSS_PROP_DOMPROP_PREFIXED */
-
-[
-
-#define PROP_STRINGIFY_INTERNAL(X) #X
-#define PROP_STRINGIFY(X) PROP_STRINGIFY_INTERNAL(X)
-
-#define DO_PROP(name, method, id, flags, pref, proptype) \
-  [ #name, #method, #id, PROP_STRINGIFY(flags), pref, proptype ],
-#define CSS_PROP(name, id, method, flags, pref, ...) \
-  DO_PROP(name, method, id, flags, pref, "longhand")
-#define CSS_PROP_SHORTHAND(name, id, method, flags, pref) \
-  DO_PROP(name, method, id, flags, pref, "shorthand")
-#define CSS_PROP_PUBLIC_OR_PRIVATE(publicname_, privatename_) publicname_
-
-#include "nsCSSPropList.h"
-
-#undef CSS_PROP_PUBLIC_OR_PRIVATE
-#undef CSS_PROP_SHORTHAND
-#undef CSS_PROP
-
-#define CSS_PROP_ALIAS(name, aliasid, id, method, pref) \
-  DO_PROP(name, method, aliasid, 0, pref, "alias")
-
-#include "nsCSSPropAliasList.h"
-
-#undef CSS_PROP_ALIAS
-
-#undef DO_PROP
-#undef PROP_STRINGIFY
-#undef PROP_STRINGIFY_INTERNAL
-
-]

--- a/layout/style/moz.build
+++ b/layout/style/moz.build
@@ -296,14 +296,14 @@ if CONFIG['COMPILE_ENVIRONMENT']:
     GENERATED_FILES += [
         'nsCSSPropsGenerated.inc',
     ]
 
     css_props = GENERATED_FILES['nsCSSPropsGenerated.inc']
     css_props.script = 'GenerateCSSPropsGenerated.py:generate'
     css_props.inputs = [
         'nsCSSPropsGenerated.inc.in',
-        'PythonCSSProps.h',
+        '!ServoCSSPropList.py',
     ]
 
     CONFIGURE_SUBST_FILES += [
         'bindgen.toml',
     ]