Make it a compile error to use a crash key with no variable name.

base/debug/crash_logging.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_DEBUG_CRASH_LOGGING_H_
 #define BASE_DEBUG_CRASH_LOGGING_H_
 
 #include <stddef.h>
 
 #include <string>
@@ skipping 37 matching lines @@
  public:
   ScopedCrashKey(const base::StringPiece& key, const base::StringPiece& value);
   ~ScopedCrashKey();
 
  private:
   std::string key_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedCrashKey);
 };
 
+#define ScopedCrashKey(x) static_assert(false, "a scoped crash key has no name")

[dcheng, 2016/07/11 01:42:44]

I'll think of a better error if people think this patch is OK. My previous
message was 81 characters >_<

[ncarter (slow), 2016/07/11 17:08:12]

How does this work with only one arg?

[dcheng, 2016/07/12 01:23:38]

I've updated this to add the appropriate number of args. It still worked (but it
complained about mismatched arg counts, rather than firing the static_assert).

Unfortunately, since this is in a namespace, it still doesn't work quite as
expected (clang complains about expecting an unqualified id). I have another
idea, but it's a bit ugly... I'll upload it once I get it working.

+
 // Before setting values for a key, all the keys must be registered.
 struct BASE_EXPORT CrashKey {
   // The name of the crash key, used in the above functions.
   const char* key_name;
 
   // The maximum length for a value. If the value is longer than this, it will
   // be truncated. If the value is larger than the |chunk_max_length| passed to
   // InitCrashKeys() but less than this value, it will be split into multiple
   // numbered chunks.
   size_t max_length;
@@ skipping 29 matching lines @@
     const base::StringPiece& value,
     size_t chunk_max_length);
 
 // Resets the crash key system so it can be reinitialized. For testing only.
 BASE_EXPORT void ResetCrashLoggingForTesting();
 
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_DEBUG_CRASH_LOGGING_H_