[AST] include decls owned by FriendDecl in -ast-dump

[hokein]

Thanks!

clang/include/clang/AST/ASTNodeTraverser.h

public:
   }
 
   void VisitUsingShadowDecl(const UsingShadowDecl *D) {
     if (auto *TD = dyn_cast<TypeDecl>(D->getUnderlyingDecl()))
       Visit(TD->getTypeForDecl());
   }
 
   void VisitFriendDecl(const FriendDecl *D) {
-    if (!D->getFriendType())
+    if (D->getFriendType()) {
+      // Traverse any CXXRecordDecl owned by this type, since
+      // it will not be in the parent context:
+      if (auto *ET = D->getFriendType()->getType()->getAs<ElaboratedType>())
+        if (auto *TD = ET->getOwnedTagDecl())
+          Visit(TD);
+    } else {
       Visit(D->getFriendDecl());
     }
+  }
 
   void VisitObjCMethodDecl(const ObjCMethodDecl *D) {
     if (D->isThisDeclarationADefinition())
       dumpDeclContext(D);
     else
       for (const ParmVarDecl *Parameter : D->parameters())
         Visit(Parameter);
 

clang/test/AST/ast-dump-decl.cpp

template<typename T> class TestFriendDecl {
   friend class A;
   friend T;
 };
 // CHECK:      CXXRecord{{.*}} TestFriendDecl
 // CHECK:        CXXRecord{{.*}} TestFriendDecl
 // CHECK-NEXT:   FriendDecl
 // CHECK-NEXT:     FunctionDecl{{.*}} foo
 // CHECK-NEXT:   FriendDecl{{.*}} 'class A':'A'
+// CHECK-NEXT:     CXXRecordDecl{{.*}} class A
 // CHECK-NEXT:   FriendDecl{{.*}} 'T'
 
 namespace TestFileScopeAsmDecl {
   asm("ret");
 }
 // CHECK:      NamespaceDecl{{.*}} TestFileScopeAsmDecl{{$}}
 // CHECK:        FileScopeAsmDecl{{.*> .*$}}
 // CHECK-NEXT:     StringLiteral