Adopt new cl::HideUnrelatedOptions API added r226729.

[beanz]

Summary

cl::HideUnrelatedOptions allows tools to hide all options not part of a specific OptionCategory. This is the common use case for cl::getRegisteredOptions, which should be deprecated in the future because it exposes implementation details of command line parsing.

[dexonsmith]

LGTM.

lib/Tooling/CommonOptionsParser.cpp

static cl::list<std::string> ArgsAfter(
       cl::desc("Additional argument to append to the compiler command line"),
       cl::cat(Category));
 
   static cl::list<std::string> ArgsBefore(
       "extra-arg-before",
       cl::desc("Additional argument to prepend to the compiler command line"),
       cl::cat(Category));
 
-  // Hide unrelated options.
-  StringMap<cl::Option*> Options;
-  cl::getRegisteredOptions(Options);
-  for (StringMap<cl::Option *>::iterator I = Options.begin(), E = Options.end();
-       I != E; ++I) {
-    if (I->second->Category != &Category && I->first() != "help" &&
-        I->first() != "version")
-      I->second->setHiddenFlag(cl::ReallyHidden);
-  }
+  cl::HideUnrelatedOptions(Category);
 
   Compilations.reset(FixedCompilationDatabase::loadFromCommandLine(argc,
                                                                    argv));
   cl::ParseCommandLineOptions(argc, argv, Overview);
   SourcePathList = SourcePaths;
   if (!Compilations) {
     std::string ErrorMessage;
     if (!BuildPath.empty()) {

tools/clang-format/ClangFormat.cpp

 static void PrintVersion() {
   raw_ostream &OS = outs();
   OS << clang::getClangToolFullVersion("clang-format") << '\n';
 }
 
 int main(int argc, const char **argv) {
   llvm::sys::PrintStackTraceOnErrorSignal();
 
-  // Hide unrelated options.
-  StringMap<cl::Option*> Options;
-  cl::getRegisteredOptions(Options);
-  for (StringMap<cl::Option *>::iterator I = Options.begin(), E = Options.end();
-       I != E; ++I) {
-    if (I->second->Category != &ClangFormatCategory && I->first() != "help" &&
-        I->first() != "version")
-      I->second->setHiddenFlag(cl::ReallyHidden);
-  }
+  cl::HideUnrelatedOptions(ClangFormatCategory);
 
   cl::SetVersionPrinter(PrintVersion);
   cl::ParseCommandLineOptions(
       argc, argv,
       "A tool to format C/C++/Obj-C code.\n\n"
       "If no arguments are specified, it formats the code from standard input\n"
       "and writes the result to the standard output.\n"
       "If <file>s are given, it reformats the files. If -i is specified\n"