Give kSyzyAsanDCheckIsFatalFeature unique linkage.

This is exploding in CheckFeatureIdentity on second use of the constexpr,
as presumably the Feature object is instantiated per call.

Bug: 763010
Change-Id: I330690fcf052a66ed3287f3a3134866025803a01
Reviewed-on: https://chromium-review.googlesource.com/674096
Commit-Queue: Sigurður Ásgeirsson <[email protected]>
Reviewed-by: Alexei Svitkine <[email protected]>
Cr-Commit-Position: refs/heads/master@{#503224}
diff --git a/base/feature_list.cc b/base/feature_list.cc
index 61ec57c..7d984f1 100644
--- a/base/feature_list.cc
+++ b/base/feature_list.cc
@@ -76,6 +76,11 @@
 
 }  // namespace
 
+#if DCHECK_IS_ON() && defined(SYZYASAN)
+const Feature kSyzyAsanDCheckIsFatalFeature{"DcheckIsFatal",
+                                            base::FEATURE_DISABLED_BY_DEFAULT};
+#endif  // defined(SYZYASAN)
+
 FeatureList::FeatureList() {}
 
 FeatureList::~FeatureList() {}