Improve the casing of Stackmap and Stacktrace.

runtime/vm/object_service.cc

Index: runtime/vm/object_service.cc
diff --git a/runtime/vm/object_service.cc b/runtime/vm/object_service.cc
index 6d2bd9ef2bf2e006d49fda1c90c136d82b2ec45a..93dfce9955c80b3f53793ee55c3318270cfe16e5 100644
--- a/runtime/vm/object_service.cc
+++ b/runtime/vm/object_service.cc
@@ -709,7 +709,7 @@ void CodeSourceMap::PrintJSONImpl(JSONStream* stream, bool ref) const {
 }
 
 
-void Stackmap::PrintJSONImpl(JSONStream* stream, bool ref) const {
+void StackMap::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Object::PrintJSONImpl(stream, ref);
 }
 
@@ -1487,7 +1487,7 @@ void Closure::PrintJSONImpl(JSONStream* stream, bool ref) const {
 }
 
 
-void Stacktrace::PrintJSONImpl(JSONStream* stream, bool ref) const {
+void StackTrace::PrintJSONImpl(JSONStream* stream, bool ref) const {
   JSONObject jsobj(stream);
   PrintSharedInstanceJSON(&jsobj, ref);
   jsobj.AddProperty("kind", "StackTrace");