Use jinja2 templating engine for Python code generators

Source/core/dom/EventFactory.cpp.tmpl

+{% from "macros.tmpl" import wrap_with_condition -%}
+
+{{ license }}
+#include "config.h"
+#include "EventFactory.h"
+
+#include "EventHeaders.h"
+#include "RuntimeEnabledFeatures.h"
+
+namespace WebCore {
+
+PassRefPtr<{{namespace}}> {{namespace}}Factory::create(const String& type)
+{
+{%- for event in events %}
+{%- call wrap_with_condition(event.conditional) %}
+    if (type == "{{event.name}}"
+        {{- " && RuntimeEnabledFeatures::" + event.runtimeConditional + "()" if event.runtimeConditional else "" -}}
+    )
+        return {{event.interfaceName}}::create();
+{%- endcall %}
+{%- endfor %}
+    return 0;
+}
+
+} // namespace WebCore
+