Switch to using SourceLocation universally in service protocol.

runtime/vm/json_stream.h

Index: runtime/vm/json_stream.h
diff --git a/runtime/vm/json_stream.h b/runtime/vm/json_stream.h
index 39bb0ac28cc81e14cbe06e32788a4942f7382e6b..c878ef7ee74aec3b770122debf8edf46d616b02f 100644
--- a/runtime/vm/json_stream.h
+++ b/runtime/vm/json_stream.h
@@ -21,6 +21,7 @@ class JSONObject;
 class MessageQueue;
 class Metric;
 class Object;
+class Script;
 class ServiceEvent;
 class Breakpoint;
 class String;
@@ -186,6 +187,10 @@ class JSONObject : public ValueObject {
 
   void AddFixedServiceId(const char* format, ...) const PRINTF_ATTRIBUTE(2, 3);
 
+  void AddLocation(const Script& script,
+                   intptr_t token_pos,
+                   intptr_t end_token_pos = -1);
+
   void AddProperty(const char* name, bool b) const {
     stream_->PrintPropertyBool(name, b);
   }