Print stack trace on exception in unit tests on Windows....

base/debug_util.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/debug_util.h"
 
 #include "base/platform_thread.h"
 
 bool DebugUtil::WaitForDebugger(int wait_seconds, bool silent) {
   for (int i = 0; i < wait_seconds * 10; ++i) {
     if (BeingDebugged()) {
       if (!silent)
         BreakDebugger();
       return true;
     }
     PlatformThread::Sleep(100);
   }
   return false;
 }
 
 const void *const *StackTrace::Addresses(size_t* count) {
-  *count = trace_.size();
-  if (trace_.size())
-    return &trace_[0];
+  *count = count_;
+  if (count_)
+    return trace_;
   return NULL;
 }