Add first sketch of the webmodules code generator.

third_party/WebKit/Source/bindings/templates/web_module_interface.cpp.tmpl

+{% filter format_blink_cpp_source_code %}
+
+{% include 'copyright_block.txt' %}
+// clang-format on
+
+#include "Web{{class_name}}.h"
+
+// TODO(dglazkov): Implement generating includes.
+{% for filename in cpp_includes %}
+#include "{{filename}}"
+{% endfor %}
+
+namespace blink {
+namespace api {
+
+// TODO(dglazkov): Implement constant generation
+{% for constant in constants %}
+// {{ constant.name }}
+{% endfor %}
+
+// TODO(dglazkov): Implement constructor generation
+
+// TODO(dglazkov): Implement attribute getter/setter generation
+{% for attribute in attributes %}
+// {{attribute.name}}
+{% endfor %}
+
+// TODO(dglazkov): Implement method generation
+{% for method in methods %}
+// {{method.cpp_type}} Cpp{{class_name}}::{{method.name}}
+{% endfor %}
+
+}  // namespace api
+}  // namespace blink
+
+{% endfilter %}