Use jinja2 for make_runtime_features and make_internal_runtime_flags

Source/core/scripts/templates/InternalRuntimeFlags.h.tmpl

+{% from "macros.tmpl" import wrap_with_condition, license -%}
+{{ license() }}
+
+#ifndef InternalRuntimeFlags_h
+#define InternalRuntimeFlags_h
+
+#include "RuntimeEnabledFeatures.h"
+#include "wtf/PassRefPtr.h"
+#include "wtf/RefPtr.h"
+#include "wtf/RefCounted.h"
+
+namespace WebCore {
+
+class InternalRuntimeFlags : public RefCounted<InternalRuntimeFlags> {
+public:
+    static PassRefPtr<InternalRuntimeFlags> create()
+    {
+        return adoptRef(new InternalRuntimeFlags);
+    }
+
+{#-
+    Setting after startup does not work for most runtime flags, but we
+    could add an option to print setters for ones which do:
+    void set{{feature.name}}Enabled(bool isEnabled) { RuntimeEnabledFeatures::set{{feature.name}}Enabled(isEnabled); }
+    If we do that, we also need to respect Internals::resetToConsistentState.
+#}
+{% for feature in features if not feature.custom %}
+{%- call wrap_with_condition(feature.condition) %}
+    bool {{feature.first_lowered_name}}Enabled() { return RuntimeEnabledFeatures::{{feature.first_lowered_name}}Enabled(); }
+{%- endcall %}
+{% endfor %}
+
+private:
+    InternalRuntimeFlags() { }
+};
+
+} // namespace WebCore
+
+#endif // InternalRuntimeFlags_h
+