Fix use of DCHECK with std::unique_ptr

DCHECK_NE comparison requires CheckOpValueStr to be defined for the
type, or providing an output stream operator. A unique_ptr does not
provide any. USE DCHECK instead.

This change was originally written by Stephan Hartmann <https://quiche-review.googlesource.com/c/quiche/+/10680>.

PiperOrigin-RevId: 353340281
Change-Id: I0bf24145007ba7e7ae2bc8a04301ec9a300e335c
diff --git a/quic/core/quic_path_validator.cc b/quic/core/quic_path_validator.cc
index ee446cc..0cc387f 100644
--- a/quic/core/quic_path_validator.cc
+++ b/quic/core/quic_path_validator.cc
@@ -68,7 +68,7 @@
 void QuicPathValidator::StartPathValidation(
     std::unique_ptr<QuicPathValidationContext> context,
     std::unique_ptr<ResultDelegate> result_delegate) {
-  DCHECK_NE(nullptr, context);
+  DCHECK(context);
   QUIC_DLOG(INFO) << "Start validating path " << *context
                   << " via writer: " << context->WriterToUse();
   if (path_context_ != nullptr) {