Simplify ASTReader ctor by using in-class initializers for many member variables

llvm-svn: 291155
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 6bdb381..2a5eda4 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -4224,25 +4224,7 @@
 ASTWriter::ASTWriter(llvm::BitstreamWriter &Stream,
                      ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions,
                      bool IncludeTimestamps)
-    : Stream(Stream), Context(nullptr), PP(nullptr), Chain(nullptr),
-      WritingModule(nullptr), IncludeTimestamps(IncludeTimestamps),
-      WritingAST(false), DoneWritingDeclsAndTypes(false),
-      ASTHasCompilerErrors(false), FirstDeclID(NUM_PREDEF_DECL_IDS),
-      NextDeclID(FirstDeclID), FirstTypeID(NUM_PREDEF_TYPE_IDS),
-      NextTypeID(FirstTypeID), FirstIdentID(NUM_PREDEF_IDENT_IDS),
-      NextIdentID(FirstIdentID), FirstMacroID(NUM_PREDEF_MACRO_IDS),
-      NextMacroID(FirstMacroID), FirstSubmoduleID(NUM_PREDEF_SUBMODULE_IDS),
-      NextSubmoduleID(FirstSubmoduleID),
-      FirstSelectorID(NUM_PREDEF_SELECTOR_IDS), NextSelectorID(FirstSelectorID),
-      NumStatements(0), NumMacros(0), NumLexicalDeclContexts(0),
-      NumVisibleDeclContexts(0), TypeExtQualAbbrev(0),
-      TypeFunctionProtoAbbrev(0), DeclParmVarAbbrev(0),
-      DeclContextLexicalAbbrev(0), DeclContextVisibleLookupAbbrev(0),
-      UpdateVisibleAbbrev(0), DeclRecordAbbrev(0), DeclTypedefAbbrev(0),
-      DeclVarAbbrev(0), DeclFieldAbbrev(0), DeclEnumAbbrev(0),
-      DeclObjCIvarAbbrev(0), DeclCXXMethodAbbrev(0), DeclRefExprAbbrev(0),
-      CharacterLiteralAbbrev(0), IntegerLiteralAbbrev(0),
-      ExprImplicitCastAbbrev(0) {
+    : Stream(Stream), IncludeTimestamps(IncludeTimestamps) {
   for (const auto &Ext : Extensions) {
     if (auto Writer = Ext->createExtensionWriter(*this))
       ModuleFileExtensionWriters.push_back(std::move(Writer));