Capture log messages via instrumentation

pkg/analyzer/lib/instrumentation/instrumentation.dart

Index: pkg/analyzer/lib/instrumentation/instrumentation.dart
diff --git a/pkg/analyzer/lib/instrumentation/instrumentation.dart b/pkg/analyzer/lib/instrumentation/instrumentation.dart
index a3c13768a9dbe8292b65ea0e15caad57270b9e69..65b47c13b4c824a94f2602e2422ced27dc3b5617 100644
--- a/pkg/analyzer/lib/instrumentation/instrumentation.dart
+++ b/pkg/analyzer/lib/instrumentation/instrumentation.dart
@@ -47,6 +47,7 @@ class InstrumentationService {
 
   static const String TAG_ERROR = 'Err';
   static const String TAG_EXCEPTION = 'Ex';
+  static const String TAG_LOG_ENTRY = 'Log';
   static const String TAG_NOTIFICATION = 'Noti';
   static const String TAG_REQUEST = 'Req';
   static const String TAG_RESPONSE = 'Res';
@@ -89,6 +90,17 @@ class InstrumentationService {
   }
 
   /**
+   * Log a log entry that was written to the analysis engine's log.
+   */
+  void logLogEntry(String level, DateTime time, String message) {
+    if (_instrumentationServer != null) {
+      String timeStamp = _toString(time);
+      _instrumentationServer.log(
+          _join([TAG_LOG_ENTRY, level, timeStamp, message]));
+    }
+  }
+
+  /**
    * Log that a notification has been sent to the client.
    */
   void logNotification(String notification) {