Support piping log data over the service protocol

runtime/vm/service_event.h

Index: runtime/vm/service_event.h
diff --git a/runtime/vm/service_event.h b/runtime/vm/service_event.h
index 8f81da5b33c38952baf917dd44bdeecc2637df91..6ebc2118b5e06106e4f2ced7707c13b1240ef944 100644
--- a/runtime/vm/service_event.h
+++ b/runtime/vm/service_event.h
@@ -34,9 +34,22 @@ class ServiceEvent {
 
     kEmbedder,
 
+    kLogging,
+
     kIllegal,
   };
 
+  struct LogRecord {
+    int64_t sequence_number;
+    int64_t timestamp;
+    intptr_t level;
+    const String* name;
+    const String* message;
+    const Instance* zone;
+    const Object* error;
+    const Instance* stack_trace;
+  };
+
   ServiceEvent(Isolate* isolate, EventKind event_kind)
       : isolate_(isolate),
         kind_(event_kind),
@@ -138,8 +151,14 @@ class ServiceEvent {
     bytes_length_ = bytes_length;
   }
 
+  void set_log_record(const LogRecord& log_record) {
+    log_record_ = log_record;
+  }
+
   void PrintJSON(JSONStream* js) const;
 
+  void PrintJSONHeader(JSONObject* jsobj) const;
+
  private:
   Isolate* isolate_;
   EventKind kind_;
@@ -153,6 +172,7 @@ class ServiceEvent {
   const Heap::GCStats* gc_stats_;
   const uint8_t* bytes_;
   intptr_t bytes_length_;
+  LogRecord log_record_;
 };
 
 }  // namespace dart