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

base/debug/crash_logging.h

Index: base/debug/crash_logging.h
diff --git a/base/debug/crash_logging.h b/base/debug/crash_logging.h
index 97bac754a4b626985fe26935d37de8008fb7f7d7..42e5bbd7e7949c23756075ae591fc43c3ffe24d9 100644
--- a/base/debug/crash_logging.h
+++ b/base/debug/crash_logging.h
@@ -55,6 +55,8 @@ class BASE_EXPORT ScopedCrashKey {
   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.