Support piping log data over the service protocol

runtime/observatory/lib/src/service/object.dart

Index: runtime/observatory/lib/src/service/object.dart
diff --git a/runtime/observatory/lib/src/service/object.dart b/runtime/observatory/lib/src/service/object.dart
index fa73cf6266a6b429e6185147b7eab837fa8af9ef..4ad633d1bcd2d99d4660b365a0399f6aedf727d1 100644
--- a/runtime/observatory/lib/src/service/object.dart
+++ b/runtime/observatory/lib/src/service/object.dart
@@ -700,6 +700,7 @@ abstract class VM extends ServiceObjectOwner {
   static const kStdoutStream = 'Stdout';
   static const kStderrStream = 'Stderr';
   static const _kGraphStream = '_Graph';
+  static const kLoggingStream = '_Logging';
 
   /// Returns a single-subscription Stream object for a VM event stream.
   Future<Stream> getEventStream(String streamId) async {
@@ -1591,6 +1592,15 @@ class DartError extends ServiceObject {
   String toString() => 'DartError($message)';
 }
 
+Level _findLogLevel(int value) {
+  for (var level in Level.LEVELS) {
+    if (level.value == value) {
+      return level;
+    }
+  }
+  return new Level('$value', value);
+}
+
 /// A [ServiceEvent] is an asynchronous event notification from the vm.
 class ServiceEvent extends ServiceObject {
   /// The possible 'kind' values.
@@ -1611,6 +1621,7 @@ class ServiceEvent extends ServiceObject {
   static const kInspect                = 'Inspect';
   static const kDebuggerSettingsUpdate = '_DebuggerSettingsUpdate';
   static const kConnectionClosed       = 'ConnectionClosed';
+  static const kLogging                = '_Logging';
 
   ServiceEvent._empty(ServiceObjectOwner owner) : super._empty(owner);
 
@@ -1629,6 +1640,7 @@ class ServiceEvent extends ServiceObject {
   @observable String reason;
   @observable String exceptions;
   @observable String bytesAsString;
+  @observable Map logRecord;
   int chunkIndex, chunkCount, nodeCount;
 
   @observable bool get isPauseEvent {
@@ -1691,6 +1703,12 @@ class ServiceEvent extends ServiceObject {
       var bytes = decodeBase64(map['bytes']);
       bytesAsString = UTF8.decode(bytes);
     }
+    if (map['logRecord'] != null) {
+      logRecord = map['logRecord'];
+      logRecord['time'] =
+          new DateTime.fromMillisecondsSinceEpoch(logRecord['time']);
+      logRecord['level'] = _findLogLevel(logRecord['level']);
+    }
   }
 
   String toString() {