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

third_party/WebKit/Source/wtf/Assertions.h

 /*
  * Copyright (C) 2003, 2006, 2007 Apple Inc.  All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 116 matching lines @@
 //  Expressions inside them are evaluated in debug builds only.
 //  They are deprecated. We should use:
 //    - DCHECK() for ASSERT()
 //    - NOTREACHED() for ASSERT_NOT_REACHED()
 #if OS(WIN)
 // FIXME: Change to use something other than ASSERT to avoid this conflict with
 // the underlying platform.
 #undef ASSERT
 #endif
 
-#define DCHECK_AT(assertion, file, line)                            \
-  LAZY_STREAM(logging::LogMessage(file, line, #assertion).stream(), \
-              DCHECK_IS_ON() ? !(assertion) : false)
+#define DCHECK_AT(assertion, file, line)                                     \
+  LAZY_STREAM(logging::LogMessage(file, line, logging::LOG_DCHECK).stream(), \
+              DCHECK_IS_ON() ? !(assertion) : false)                         \
+      << "Check failed: " #assertion ". "
 
 #if DCHECK_IS_ON()
 #define ASSERT(assertion) DCHECK(assertion)
 #define ASSERT_NOT_REACHED() NOTREACHED()
 #else
 #define ASSERT(assertion) ((void)0)
 #define ASSERT_NOT_REACHED() ((void)0)
 #endif
 
 // Users must test "#if ENABLE(SECURITY_ASSERT)", which helps ensure
@@ skipping 99 matching lines @@
     return static_cast<thisType&>(argument);                                  \
   }                                                                           \
   inline const thisType& to##thisType##OrDie(const argumentType& argument) {  \
     CHECK(referencePredicate);                                                \
     return static_cast<const thisType&>(argument);                            \
   }                                                                           \
   void to##thisType##OrDie(const thisType*);                                  \
   void to##thisType##OrDie(const thisType&)
 
 #endif  // WTF_Assertions_h