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

base/debug/crash_logging.cc

Index: base/debug/crash_logging.cc
diff --git a/base/debug/crash_logging.cc b/base/debug/crash_logging.cc
index 058b476800da3a65bd35f3b6cb2f804533986e26..2bd4effd1f9193efd1e8ce880611d83fd0675765 100644
--- a/base/debug/crash_logging.cc
+++ b/base/debug/crash_logging.cc
@@ -13,6 +13,8 @@
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 
+#undef ScopedCrashKey

[danakj, 2016/07/19 02:14:05]

The precompiler will replace the constructor defn with the macro otherwise?

[dcheng, 2016/07/19 02:34:34]

Yeah, this will garble the ctor. So this is a dumb hack to make it not shoot
itself in the foot.

[danakj, 2016/07/19 21:02:56]

OK can you leave a quick comment on that.

[dcheng, 2016/07/22 05:39:22]

Done.

+
 namespace base {
 namespace debug {