Print stack traces in child processes when browser tests failed.

content/app/content_main_runner.cc

Index: content/app/content_main_runner.cc
diff --git a/content/app/content_main_runner.cc b/content/app/content_main_runner.cc
index df069e87e07a6c77125fe6af3f16f93918126926..55c6ac7f651137d6e9f55fb46e0de6c78a286754 100644
--- a/content/app/content_main_runner.cc
+++ b/content/app/content_main_runner.cc
@@ -10,6 +10,7 @@
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/debug/debugger.h"
+#include "base/debug/stack_trace.h"
 #include "base/files/file_path.h"
 #include "base/i18n/icu_util.h"
 #include "base/lazy_instance.h"
@@ -195,6 +196,15 @@ void CommonSubprocessInit(const std::string& process_type) {
   // surface UI -- but it's likely they get this wrong too so why not.
   setlocale(LC_NUMERIC, "C");
 #endif
+
+#if !defined(OFFICIAL_BUILD)
+  // Print stack traces to stderr when crashes occur. This opens up security
+  // holes so it should never be enabled for official builds.
+  base::debug::EnableInProcessStackDumping();
+#if defined(OS_WIN)
+  LoadLibraryA("dbghelp.dll");
+#endif
+#endif
 }
 
 class ContentClientInitializer {