Extract PerformanceLogger from AnalysisDriver.

pkg/analyzer/lib/src/dart/analysis/file_tracker.dart

 // Copyright (c) 2017, 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.
 
 import 'dart:collection';
 
-import 'package:analyzer/src/dart/analysis/driver.dart';
 import 'package:analyzer/src/dart/analysis/file_state.dart';
+import 'package:front_end/src/base/performace_logger.dart';
 
 /**
  * Callback used by [FileTracker] to report to its client that files have been
  * added, changed, or removed, and therefore more analysis may be necessary.
  */
 typedef void FileTrackerChangeHook();
 
 /**
  * Maintains the file system state needed by the analysis driver, as well as
  * information about files that have changed and the impact of those changes.
@@ skipping 267 matching lines @@
       // If the file has not been accessed yet, we either will eventually read
       // it later while analyzing one of the added files, or don't need it.
       if (_fsState.knownFilePaths.contains(path)) {
         verifyApiSignature(path);
       }
       return true;
     }
     return false;
   }
 }