Fix sense of CheckOpResult comment.

Review URL: https://codereview.chromium.org/1808053002

Cr-Commit-Position: refs/heads/master@{#382056}


CrOS-Libchrome-Original-Commit: b7662fc32246dda98df64fd8aa41fddbaae7d2be
diff --git a/base/logging.h b/base/logging.h
index adf8fde..2c8959c 100644
--- a/base/logging.h
+++ b/base/logging.h
@@ -430,7 +430,7 @@
 // boolean.
 class CheckOpResult {
  public:
-  // |message| must be null if and only if the check failed.
+  // |message| must be non-null iff the check failed.
   CheckOpResult(std::string* message) : message_(message) {}
   // Returns true if the check succeeded.
   operator bool() const { return !message_; }