Remove more blink modules gypi code.

third_party/WebKit/Source/core/BUILD.gn

Index: third_party/WebKit/Source/core/BUILD.gn
diff --git a/third_party/WebKit/Source/core/BUILD.gn b/third_party/WebKit/Source/core/BUILD.gn
index 49fc5a105cb7afd332895cae45522a88c79d5c99..02744057f27f7482d3c1cfc80983afa7bd0bd10d 100644
--- a/third_party/WebKit/Source/core/BUILD.gn
+++ b/third_party/WebKit/Source/core/BUILD.gn
@@ -505,14 +505,11 @@ process_in_files("make_core_generated_svg_element_type_helpers") {
 
 # make_event_factory -----------------------------------------------------------
 
-process_in_files("make_core_generated_event_factory") {
-  script = "../build/scripts/make_event_factory.py"
-
+make_event_factory("make_core_generated_event_factory") {
   in_files = [
     "$blink_core_output_dir/EventInterfaces.in",
     "events/EventAliases.in",
   ]
-  other_inputs = make_event_factory_files
   outputs = [
     "$blink_core_output_dir/Event.cpp",
     "$blink_core_output_dir/EventHeaders.h",