Improve display of simd vector types and stack traces in Observatory.

runtime/vm/object.h

Index: runtime/vm/object.h
diff --git a/runtime/vm/object.h b/runtime/vm/object.h
index 236814749f8e1fba1a14e091000096b092f4244f..4243f0c46b338ff434ff18b443e2227947562899 100644
--- a/runtime/vm/object.h
+++ b/runtime/vm/object.h
@@ -7655,8 +7655,6 @@ class Stacktrace : public Instance {
                             const Array& pc_offset_array,
                             Heap::Space space = Heap::kNew);
 
-  RawString* FullStacktrace() const;
-
   // The argument 'max_frames' limits the number of printed frames.
   const char* ToCStringInternal(intptr_t* frame_index,
                                 intptr_t max_frames = kMaxInt32) const;