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

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index dddddfb9de4ed94c1d5d25cc1ce9f3cd62fe2a85..c638cb935d4e9578d7a2d5f93b547954425400ae 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -20375,7 +20375,11 @@ const char* Float32x4::ToCString() const {
 
 
 void Float32x4::PrintJSONImpl(JSONStream* stream, bool ref) const {
-  Instance::PrintJSONImpl(stream, ref);
+  JSONObject jsobj(stream);
+  PrintSharedInstanceJSON(&jsobj, ref);
+  jsobj.AddProperty("kind", "Float32x4");
+  jsobj.AddServiceId(*this);
+  jsobj.AddProperty("valueAsString", ToCString());
 }
 
 
@@ -20480,7 +20484,11 @@ const char* Int32x4::ToCString() const {
 
 
 void Int32x4::PrintJSONImpl(JSONStream* stream, bool ref) const {
-  Instance::PrintJSONImpl(stream, ref);
+  JSONObject jsobj(stream);
+  PrintSharedInstanceJSON(&jsobj, ref);
+  jsobj.AddProperty("kind", "Int32x4");
+  jsobj.AddServiceId(*this);
+  jsobj.AddProperty("valueAsString", ToCString());
 }
 
 
@@ -20560,7 +20568,11 @@ const char* Float64x2::ToCString() const {
 
 
 void Float64x2::PrintJSONImpl(JSONStream* stream, bool ref) const {
-  Instance::PrintJSONImpl(stream, ref);
+  JSONObject jsobj(stream);
+  PrintSharedInstanceJSON(&jsobj, ref);
+  jsobj.AddProperty("kind", "Float64x2");
+  jsobj.AddServiceId(*this);
+  jsobj.AddProperty("valueAsString", ToCString());
 }
 
 
@@ -20922,20 +20934,19 @@ RawStacktrace* Stacktrace::New(const Array& code_array,
 }
 
 
-RawString* Stacktrace::FullStacktrace() const {
-  intptr_t idx = 0;
-  return String::New(ToCStringInternal(&idx));
-}
-
-
 const char* Stacktrace::ToCString() const {
-  const String& trace = String::Handle(FullStacktrace());
-  return trace.ToCString();
+  intptr_t idx = 0;
+  return ToCStringInternal(&idx);
 }
 
 
 void Stacktrace::PrintJSONImpl(JSONStream* stream, bool ref) const {
-  Instance::PrintJSONImpl(stream, ref);
+  JSONObject jsobj(stream);
+  PrintSharedInstanceJSON(&jsobj, ref);
+  jsobj.AddProperty("kind", "StackTrace");
+  jsobj.AddServiceId(*this);
+  intptr_t idx = 0;
+  jsobj.AddProperty("valueAsString", ToCStringInternal(&idx));
 }