[Mac] Capture -dealloc backtrace to log with CrZombie messages.

base/debug/stack_trace.cc

Index: base/debug/stack_trace.cc
diff --git a/base/debug/stack_trace.cc b/base/debug/stack_trace.cc
index 7c44f7afeaef3f3ace0d3839c8dd51939ace635c..fc34ad0f8b5ac2b26855aebbac888c43e1f8b694 100644
--- a/base/debug/stack_trace.cc
+++ b/base/debug/stack_trace.cc
@@ -4,9 +4,22 @@
 
 #include "base/debug/stack_trace.h"
 
+#include "base/basictypes.h"
+
+#include <string.h>
+
+#include <algorithm>
+
 namespace base {
 namespace debug {
 
+StackTrace::StackTrace(const void* const* trace, size_t count) {
+  count = std::min(count, arraysize(trace_));
+  if (count)
+    memcpy(trace_, trace, count * sizeof(trace_[0]));
+  count_ = count;
+}
+
 StackTrace::~StackTrace() {
 }