Force crash on Mac10.9- in BreakDebugger()

base/debug/debugger_posix.cc

Index: base/debug/debugger_posix.cc
diff --git a/base/debug/debugger_posix.cc b/base/debug/debugger_posix.cc
index e92d5a5619a6f113ad5b7adc5fdb92af7a541b46..e0295fdedb8660285de6c77dd663e9978360c0c5 100644
--- a/base/debug/debugger_posix.cc
+++ b/base/debug/debugger_posix.cc
@@ -26,6 +26,9 @@
 
 #if defined(OS_MACOSX)
 #include <AvailabilityMacros.h>
+#if !defined(OS_IOS)
+#include "base/mac/mac_util.h"
+#endif
 #endif
 
 #if defined(OS_MACOSX) || defined(OS_BSD)
@@ -231,7 +234,13 @@ void DebugBreak() {
 }  // namespace
 #define DEBUG_BREAK() DebugBreak()
 #elif defined(DEBUG_BREAK_ASM)
-#define DEBUG_BREAK() DEBUG_BREAK_ASM()
+#define DEBUG_BREAK() \
+  do { \
+    if (base::mac::IsAtMostOS10_9()) \
+      *static_cast<volatile int*>(0) = 0; \
+    else \
+      DEBUG_BREAK_ASM(); \
+  } while (false)
 #else
 #error "Don't know how to debug break on this architecture/OS"
 #endif