[clang-format] pass Style by reference instead of value.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@272465 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Format/Format.cpp

@@ -1457,7 +1457,7 @@ bool checkAndConsumeDirectiveWithName(Lexer &Lex, StringRef Name, Token &Tok) {
 
 unsigned getOffsetAfterHeaderGuardsAndComments(StringRef FileName,
                                                StringRef Code,
-                                               FormatStyle Style) {
+                                               const FormatStyle &Style) {
   std::unique_ptr<Environment> Env =
       Environment::CreateVirtualEnvironment(Code, FileName, /*Ranges=*/{});
   const SourceManager &SourceMgr = Env->getSourceManager();