[Mac] Record backtrace with nsexception logging.

chrome/common/crash_keys.cc

Index: chrome/common/crash_keys.cc
diff --git a/chrome/common/crash_keys.cc b/chrome/common/crash_keys.cc
index 3eb95714e8e981fefdf64f81f9d09b7aaa359af9..155c8b24424c0718fef2b2c3b298a867ba48d23c 100644
--- a/chrome/common/crash_keys.cc
+++ b/chrome/common/crash_keys.cc
@@ -55,6 +55,7 @@ size_t RegisterChromeCrashKeys() {
     { mac::kLastNSException, kMediumSize },
     { mac::kLastNSExceptionTrace, kMediumSize },
     { mac::kNSException, kMediumSize },
+    { mac::kNSExceptionTrace, kMediumSize },
     { mac::kSendAction, kMediumSize },
     { mac::kZombie, kMediumSize },
     { mac::kZombieTrace, kMediumSize },
@@ -80,6 +81,7 @@ const char kLastNSException[] = "lastexception";
 const char kLastNSExceptionTrace[] = "lastexception_bt";
 
 const char kNSException[] = "nsexception";
+const char kNSExceptionTrace[] = "nsexception_bt";
 
 const char kSendAction[] = "sendaction";