Move QuicClock to third_party/quic/core.

It has never had a platform impl, and thus should not be in quic/platform/api.

gfe-relnote: n/a (no functional change)
PiperOrigin-RevId: 294522346
Change-Id: Ibba0760f4a5a8c9a59c5eb3796b17f11f8a1a87d
diff --git a/quic/quartc/quartc_fakes.h b/quic/quartc/quartc_fakes.h
index 41594df..94bf1ad 100644
--- a/quic/quartc/quartc_fakes.h
+++ b/quic/quartc/quartc_fakes.h
@@ -7,9 +7,9 @@
 
 #include <string>
 
+#include "net/third_party/quiche/src/quic/core/quic_clock.h"
 #include "net/third_party/quiche/src/quic/core/quic_error_codes.h"
 #include "net/third_party/quiche/src/quic/core/quic_types.h"
-#include "net/third_party/quiche/src/quic/platform/api/quic_clock.h"
 #include "net/third_party/quiche/src/quic/quartc/quartc_endpoint.h"
 #include "net/third_party/quiche/src/quic/quartc/quartc_session.h"
 #include "net/third_party/quiche/src/quic/quartc/quartc_stream.h"