Duplicated mimetype constants

ProjectExplorer::Constants and CppTools::Constants have some entries which have the same variable name and the same value:

const char C_HEADER_MIMETYPE[] = "text/x-chdr";
const char C_SOURCE_MIMETYPE[] = "text/x-csrc";
const char CPP_HEADER_MIMETYPE[] = "text/x-c++hdr";
const char CPP_SOURCE_MIMETYPE[] = "text/x-c++src";

Shall we deduplicate them? Feel free to assign this to me.