Rework analysis server performance measurement code.

pkg/analyzer/lib/src/generated/source_io.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.source.io;
 
 import 'engine.dart';
@@ skipping 111 matching lines @@
   /**
    * Initialize a newly created source object.
    *
    * @param file the file represented by this source
    * @param uri the URI from which this source was originally derived
    */
   FileBasedSource.con2(this.uri, this.file);
 
   @override
   TimestampedData<String> get contents {
-    TimeCounter_TimeCounterHandle handle = PerformanceStatistics.io.start();
+    PerformanceTag prevTag = PerformanceStatistics.io.makeCurrent();
     try {
       return contentsFromFile;
     } finally {
-      _reportIfSlowIO(handle.stop());
+      prevTag.makeCurrent();
     }
   }
 
   /**
    * Get the contents and timestamp of the underlying file.
    *
    * Clients should consider using the the method [AnalysisContext.getContents]
    * because contexts can have local overrides of the content of a source that the source is not
    * aware of.
    *
@@ skipping 81 matching lines @@
     }
   }
 
   @override
   String toString() {
     if (file == null) {
       return "<unknown source>";
     }
     return file.getAbsolutePath();
   }
-
-  /**
-   * Record the time the IO took if it was slow
-   */
-  void _reportIfSlowIO(int nanos) {
-    // TODO(brianwilkerson) Decide whether we still want to capture this data.
-//    //If slower than 10ms
-//    if (nanos > 10 * TimeCounter.NANOS_PER_MILLI) {
-//      InstrumentationBuilder builder = Instrumentation.builder2("SlowIO");
-//      try {
-//        builder.data3("fileName", fullName);
-//        builder.metric2("IO-Time-Nanos", nanos);
-//      } finally {
-//        builder.log();
-//      }
-//    }
-  }
 }
 
 /**
  * Instances of the class `FileUriResolver` resolve `file` URI's.
  */
 class FileUriResolver extends UriResolver {
   /**
    * The name of the `file` scheme.
    */
   static String FILE_SCHEME = "file";
@@ skipping 273 matching lines @@
   }
 
   /**
    * Return `true` if the given URI is a `file` URI.
    *
    * @param uri the URI being tested
    * @return `true` if the given URI is a `file` URI
    */
   static bool isFileUri(Uri uri) => uri.scheme == FILE_SCHEME;
 }