Implement Dump-on-DCHECK (via a new LogSeverity).

base/logging.h

Index: base/logging.h
diff --git a/base/logging.h b/base/logging.h
index 7854e3934e974b4670930d6855f3ab8699a8376f..7a60aa7496609694d9fe3ef27660705065da4648 100644
--- a/base/logging.h
+++ b/base/logging.h
@@ -297,10 +297,13 @@ const LogSeverity LOG_INFO = 0;
 const LogSeverity LOG_WARNING = 1;
 const LogSeverity LOG_ERROR = 2;
 const LogSeverity LOG_FATAL = 3;
-const LogSeverity LOG_NUM_SEVERITIES = 4;
+const LogSeverity LOG_DUMP = 4;

[Wez, 2017/01/15 01:18:42]

gab, danakj: I'm concerned about adding this new LogSeverity, and expect that
there will be a load of sites that don't handle the new value (which should be
treated similarly to LOG_FATAL or LOG_ERROR in most cases).

How would you feel about moving the non-verbose log severities into an enum, so
that most call-sites can continue to use the integer form, but call-sites which
expect a non-verbose severity and switch based on it can be made checked more
easily?

+const LogSeverity LOG_NUM_SEVERITIES = 5;
 
 // LOG_DFATAL is LOG_FATAL in debug mode, ERROR in normal mode
-#ifdef NDEBUG
+#if defined(DCHECK_IS_DUMP_WITHOUT_CRASH)
+const LogSeverity LOG_DFATAL = LOG_DUMP;
+#elif NDEBUG
 const LogSeverity LOG_DFATAL = LOG_ERROR;
 #else
 const LogSeverity LOG_DFATAL = LOG_FATAL;
@@ -694,9 +697,9 @@ enum { DEBUG_MODE = DCHECK_IS_ON() };
 #if DCHECK_IS_ON()
 
 #define COMPACT_GOOGLE_LOG_EX_DCHECK(ClassName, ...) \
-  COMPACT_GOOGLE_LOG_EX_FATAL(ClassName , ##__VA_ARGS__)
-#define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_FATAL
-const LogSeverity LOG_DCHECK = LOG_FATAL;
+  COMPACT_GOOGLE_LOG_EX_DFATAL(ClassName, ##__VA_ARGS__)
+#define COMPACT_GOOGLE_LOG_DCHECK COMPACT_GOOGLE_LOG_DFATAL
+const LogSeverity LOG_DCHECK = LOG_DFATAL;
 
 #else  // DCHECK_IS_ON()