fix: compilation error on upstream Clang

The existing code relied on Clang not evaluating constant arguments
unless they were used, which affected UpdateContainerPolicy in
DOMFeaturePolicy. This was fixed in LLVM/Clang r361670[1].

[1] https://github.com/llvm/llvm-project/commit/de47d66191e50e8a741ed551c25d60bbf86da5e4?

Change-Id: Ie97d33f4cb98bd627ac4271c9a4d3d904d686883
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1635489Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Richard Townsend <richard.townsend@arm.com>
Cr-Commit-Position: refs/heads/master@{#664330}

third_party/blink/renderer/core/feature_policy/dom_feature_policy.h

@@ -9,6 +9,7 @@
 #include "third_party/blink/renderer/core/core_export.h"
 #include "third_party/blink/renderer/platform/bindings/script_wrappable.h"
 #include "third_party/blink/renderer/platform/heap/member.h"
+#include "third_party/blink/renderer/platform/weborigin/security_origin.h"
 
 namespace blink {