[NFC] Move DeclID from serialization/ASTBitCodes.h to AST/DeclID.h (#89873)

Previously, the DeclID is defined in serialization/ASTBitCodes.h under
clang::serialization namespace. However, actually the DeclID is not
purely used in serialization part. The DeclID is already widely used in
AST and all around the clang project via classes like `LazyPtrDecl` or
calling `ExternalASTSource::getExernalDecl()`. All such uses are via the
raw underlying type of `DeclID` as `uint32_t`. This is not pretty good.

This patch moves the DeclID class family to a new header `AST/DeclID.h`
so that the whole project can use the wrapped class `DeclID`,
`GlobalDeclID` and `LocalDeclID` instead of the raw underlying type.
This can improve the readability and the type safety.

1 files changed, 1 insertions, 1 deletions

diff --git a/clang/lib/Sema/MultiplexExternalSemaSource.cpp b/clang/lib/Sema/MultiplexExternalSemaSource.cpp
index 6a5f9f6..e48c724 100644
--- a/clang/lib/Sema/MultiplexExternalSemaSource.cpp
+++ b/clang/lib/Sema/MultiplexExternalSemaSource.cpp
@@ -46,7 +46,7 @@ void MultiplexExternalSemaSource::AddSource(ExternalSemaSource *Source) {
 // ExternalASTSource.
 //===----------------------------------------------------------------------===//
 
-Decl *MultiplexExternalSemaSource::GetExternalDecl(Decl::DeclID ID) {
+Decl *MultiplexExternalSemaSource::GetExternalDecl(DeclID ID) {
   for(size_t i = 0; i < Sources.size(); ++i)
     if (Decl *Result = Sources[i]->GetExternalDecl(ID))
       return Result;