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

runtime/vm/service/service.md

Index: runtime/vm/service/service.md
diff --git a/runtime/vm/service/service.md b/runtime/vm/service/service.md
index 3b24aee6000f3918a44cb00b76a8550134e2c865..c18f390d9bc59962a9686c5b0dea7e7e7e99e268 100644
--- a/runtime/vm/service/service.md
+++ b/runtime/vm/service/service.md
@@ -1241,6 +1241,10 @@ class @Instance extends @Object {
   //   Double (suitable for passing to Double.parse())
   //   Int (suitable for passing to int.parse())
   //   String (value may be truncated)
+  //   Float32x4
+  //   Float64x2
+  //   Int32x4
+  //   StackTrace
   string valueAsString [optional];
 
   // The valueAsString for String references may be truncated. If so,
@@ -1507,6 +1511,11 @@ enum InstanceKind {
   // Maps will be PlainInstance.
   Map,
 
+  // Vector instance kinds.
+  Float32x4,
+  Float64x2,
+  Int32x4
+
   // An instance of the built-in VM TypedData implementations.  User-defined
   // TypedDatas will be PlainInstance.
   Uint8ClampedList,
@@ -1524,6 +1533,9 @@ enum InstanceKind {
   Float32x4List,
   Float64x2List,
 
+  // An instance of the Dart class StackTrace.
+  StackTrace,
+
   // An instance of the built-in VM Closure implementation. User-defined
   // Closures will be PlainInstance.
   Closure,