Added CSSPropertyAPIMethods.json5 which defines all API methods.

third_party/WebKit/Source/build/scripts/scripts.gni

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/toolchain/toolchain.gni")
 import("//third_party/WebKit/Source/config.gni")
 
 # All paths in this file should be absolute so targets in any directory can use
 # them without worrying about the current directory.
 _scripts_dir = "//third_party/WebKit/Source/build/scripts"
@@ skipping 119 matching lines @@
   }
 }
 
 # Template for scripts using css_properties.py. This is a special case of
 # process_in_files.
 #   outputs: expected results
 template("css_properties") {
   process_in_files(target_name) {
     script = invoker.script
     in_files = [ "css/CSSProperties.json5" ]
+    if (defined(invoker.in_files)) {
+      in_files += invoker.in_files
+    }
     other_inputs = css_properties_files
     if (defined(invoker.other_inputs)) {
       other_inputs += invoker.other_inputs
     }
     other_args = [
       "--gperf",
       gperf_exe,
     ]
     outputs = invoker.outputs
   }
@@ skipping 45 matching lines @@
     other_inputs = make_event_factory_files
     forward_variables_from(invoker,
                            [
                              "deps",
                              "in_files",
                              "outputs",
                              "visibility",
                            ])
   }
 }