Make Decl::setOwningModuleID() public. (NFC)

This API is going to be used by LLDB to recreate owning module
information for Decls deserialized from DWARF.

Differential Revision: https://reviews.llvm.org/D75560

clang/include/clang/AST/Decl.h

@@ -3539,6 +3539,7 @@ class EnumDecl : public TagDecl {
   /// negative enumerators of this enum. (see getNumNegativeBits)
   void setNumNegativeBits(unsigned Num) { EnumDeclBits.NumNegativeBits = Num; }
 
+public:
   /// True if this tag declaration is a scoped enumeration. Only
   /// possible in C++11 mode.
   void setScoped(bool Scoped = true) { EnumDeclBits.IsScoped = Scoped; }
@@ -3555,6 +3556,7 @@ class EnumDecl : public TagDecl {
   /// Microsoft-style enumeration with a fixed underlying type.
   void setFixed(bool Fixed = true) { EnumDeclBits.IsFixed = Fixed; }
 
+private:
   /// True if a valid hash is stored in ODRHash.
   bool hasODRHash() const { return EnumDeclBits.HasODRHash; }
   void setHasODRHash(bool Hash = true) { EnumDeclBits.HasODRHash = Hash; }

clang/include/clang/AST/DeclBase.h

@@ -626,7 +626,16 @@ protected:
     setModuleOwnershipKind(ModuleOwnershipKind::ModulePrivate);
   }
 
-  /// Set the owning module ID.
+public:
+  /// Set the FromASTFile flag. This indicates that this declaration
+  /// was deserialized and not parsed from source code and enables
+  /// features such as module ownership information.
+  void setFromASTFile() {
+    FromASTFile = true;
+  }
+
+  /// Set the owning module ID.  This may only be called for
+  /// deserialized Decls.
   void setOwningModuleID(unsigned ID) {
     assert(isFromASTFile() && "Only works on a deserialized declaration");
     *((unsigned*)this - 2) = ID;

clang/include/clang/AST/DeclCXX.h

@@ -2722,8 +2722,6 @@ class CXXConversionDecl : public CXXMethodDecl {
 
   ExplicitSpecifier ExplicitSpec;
 
-  void setExplicitSpecifier(ExplicitSpecifier ES) { ExplicitSpec = ES; }
-
 public:
   friend class ASTDeclReader;
   friend class ASTDeclWriter;
@@ -2745,6 +2743,7 @@ public:
 
   /// Return true if the declartion is already resolved to be explicit.
   bool isExplicit() const { return getExplicitSpecifier().isExplicit(); }
+  void setExplicitSpecifier(ExplicitSpecifier ES) { ExplicitSpec = ES; }
 
   /// Returns the type that this conversion function is converting to.
   QualType getConversionType() const {

clang/include/clang/AST/DeclTemplate.h

@@ -1891,6 +1891,10 @@ public:
     return *TemplateArgs;
   }
 
+  void setTemplateArgs(TemplateArgumentList *Args) {
+    TemplateArgs = Args;
+  }
+
   /// Determine the kind of specialization that this
   /// declaration represents.
   TemplateSpecializationKind getSpecializationKind() const {