Use jinja2 templating engine for Python code generators

Source/core/page/RuntimeEnabledFeatures.h.tmpl

+{% from "macros.tmpl" import wrap_with_condition -%}
+
+{{ license }}
+#ifndef RuntimeEnabledFeatures_h
+#define RuntimeEnabledFeatures_h
+
+namespace WebCore {
+
+// A class that stores static enablers for all experimental features.
+
+class RuntimeEnabledFeatures {
+public:
+{%- for feature in features %}
+{%- if feature.custom %}
+    static bool {{feature.first_lowered_name}}Enabled();
+{%- else %}
+{%- if feature.condition %}
+#if ENABLE({{feature.condition}})
+{%- endif %}
+    static void set{{feature.name}}Enabled(bool isEnabled) { is{{feature.name}}Enabled = isEnabled; }
+    static bool {{feature.first_lowered_name}}Enabled() { return {{feature.enabled_condition}}; }
+{%- if feature.condition %}
+#else
+    static void set{{feature.name}}Enabled(bool) { }
+    static bool {{feature.first_lowered_name}}Enabled() { return false; }
+#endif
+{%- endif %}
+{%- endif %}
+{% endfor %}
+
+private:
+    RuntimeEnabledFeatures() { }
+
+{% for feature in features if not feature.custom %}
+{%- call wrap_with_condition(feature.condition) %}
+    static bool is{{feature.name}}Enabled;
+{%- endcall %}
+{%- endfor %}
+};
+
+} // namespace WebCore
+
+#endif // RuntimeEnabledFeatures_h
+