WARN_UNUSED_RESULT on all Thread/SequenceChecker impls

base/sequence_checker.h

Index: base/sequence_checker.h
diff --git a/base/sequence_checker.h b/base/sequence_checker.h
index 20d7f25d73684a16dfd440d130e4dad459962e27..3653fbc92ac8b4eb37c123fa00c7b35f7abb3714 100644
--- a/base/sequence_checker.h
+++ b/base/sequence_checker.h
@@ -5,6 +5,7 @@
 #ifndef BASE_SEQUENCE_CHECKER_H_
 #define BASE_SEQUENCE_CHECKER_H_
 
+#include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/sequence_checker_impl.h"
 
@@ -66,7 +67,7 @@ namespace base {
 // above macros) to get the right version for your build configuration.
 class SequenceCheckerDoNothing {
  public:
-  bool CalledOnValidSequence() const { return true; }
+  bool CalledOnValidSequence() const WARN_UNUSED_RESULT { return true; }
 
   void DetachFromSequence() {}
 };