Dump stack trace on segfault in the VM.

runtime/vm/profiler.h

Index: runtime/vm/profiler.h
diff --git a/runtime/vm/profiler.h b/runtime/vm/profiler.h
index 1ea5f2dac223ca1cefa1fc24b93e1d6893362f38..5b86c55c2f2ff666ee30227a57a2584628ee0de7 100644
--- a/runtime/vm/profiler.h
+++ b/runtime/vm/profiler.h
@@ -54,6 +54,7 @@ class Profiler : public AllStatic {
 
   static SampleBuffer* sample_buffer() { return sample_buffer_; }
 
+  static void DumpStackTrace(void* context);
   static void DumpStackTrace(bool native_stack_trace = true);
 
   static void SampleAllocation(Thread* thread, intptr_t cid);
@@ -74,6 +75,11 @@ class Profiler : public AllStatic {
   }
 
  private:
+  static void DumpStackTrace(bool native_stack_trace,
+                             uword sp,
+                             uword fp,
+                             uword pc);
+
   // Does not walk the thread's stack.
   static void SampleThreadSingleFrame(Thread* thread, uintptr_t pc);
   static bool initialized_;