Added CSSPropertyAPIMethods.json5 which defines all API methods.

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

Index: third_party/WebKit/Source/build/scripts/scripts.gni
diff --git a/third_party/WebKit/Source/build/scripts/scripts.gni b/third_party/WebKit/Source/build/scripts/scripts.gni
index 4b35a41e182761e0229af02317825320d3f60f88..258dbbbbfec5dd2b0936d16fde839bb3e6dcf718 100644
--- a/third_party/WebKit/Source/build/scripts/scripts.gni
+++ b/third_party/WebKit/Source/build/scripts/scripts.gni
@@ -26,6 +26,11 @@ scripts_for_in_files = [
 css_properties_files =
     scripts_for_in_files + [ "$_scripts_dir/css_properties.py" ]
 
+make_css_property_api_files = [
+  "$_scripts_dir/templates/CSSPropertyAPIFiles.h.tmpl",
+  "$_scripts_dir/templates/CSSPropertyDescriptor.cpp.tmpl",
+]
+
 make_event_factory_files = scripts_for_in_files + [
                              "$_scripts_dir/make_event_factory.py",
                              "$_scripts_dir/templates/EventFactory.cpp.tmpl",
@@ -183,6 +188,20 @@ template("make_qualified_names") {
   }
 }
 
+# Template to run the make_css_property_apis script. This is a special case of
+# process_in_files.
+#   in_files: list of ".json5" files to process.
+#   outputs: list of output files
+template("make_css_property_apis") {
+  process_in_files(target_name) {
+    script =
+        "//third_party/WebKit/Source/build/scripts/make_css_property_apis.py"
+    in_files = invoker.in_files
+    other_inputs = make_css_property_api_files
+    outputs = invoker.outputs
+  }
+}
+
 # Calls the make_event_factory script. This is a special case of
 # process_in_files.
 #   in_files: list of ".in" files to process.