[clang-format] Refactor ShouldBreakBeforeBrace to use switch. NFC.

Author: mkurdej

clang/lib/Format/UnwrappedLineParser.cpp

@@ -897,17 +897,24 @@ static bool isIIFE(const UnwrappedLine &Line,
 
 static bool ShouldBreakBeforeBrace(const FormatStyle &Style,
                                    const FormatToken &InitialToken) {
-  if (InitialToken.isOneOf(tok::kw_namespace, TT_NamespaceMacro))
+  tok::TokenKind Kind = InitialToken.Tok.getKind();
+  if (InitialToken.is(TT_NamespaceMacro))
+    Kind = tok::kw_namespace;
+
+  switch (Kind) {
+  case tok::kw_namespace:
     return Style.BraceWrapping.AfterNamespace;
-  if (InitialToken.is(tok::kw_class))
+  case tok::kw_class:
     return Style.BraceWrapping.AfterClass;
-  if (InitialToken.is(tok::kw_union))
+  case tok::kw_union:
     return Style.BraceWrapping.AfterUnion;
-  if (InitialToken.is(tok::kw_struct))
+  case tok::kw_struct:
     return Style.BraceWrapping.AfterStruct;
-  if (InitialToken.is(tok::kw_enum))
+  case tok::kw_enum:
     return Style.BraceWrapping.AfterEnum;
-  return false;
+  default:
+    return false;
+  }
 }
 
 void UnwrappedLineParser::parseChildBlock(