update the analyzer and analysis server perf tags

pkg/analyzer/lib/src/task/driver.dart

 // Copyright (c) 2015, 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.
 
 library analyzer.src.task.driver;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 import 'package:analyzer/src/generated/utilities_general.dart';
 import 'package:analyzer/src/task/inputs.dart';
 import 'package:analyzer/src/task/manager.dart';
 import 'package:analyzer/task/model.dart';
 
+final PerformanceTag driverTag =
+    PerformanceStatistics.analyzer.createChild('driver');

[scheglov, 2017/06/04 00:30:44]

Hm...
We use this tag for different "drivers".

[devoncarew, 2017/06/04 01:45:53]

Updated this one to be 'taskDriver'.

+
+final PerformanceTag driverCacheTag = driverTag.createChild('cache');

[scheglov, 2017/06/04 00:30:44]

Unless I miss something, we use this for the different driver.
So, maybe we should move it there.

[devoncarew, 2017/06/04 01:45:53]

Moved these to 'analysis/driver.dart'.

There are a lot of drivers :)

+
 final PerformanceTag analysisDriverProcessOutputs =
-    new PerformanceTag('AnalysisDriver.processOutputs');
+    driverTag.createChild('processOutputs');
 
 final PerformanceTag workOrderMoveNextPerformanceTag =
-    new PerformanceTag('WorkOrder.moveNext');
+    driverTag.createChild('workOrderMoveNext');
 
 /**
  * An object that is used to cause analysis to be performed until all of the
  * required analysis information has been computed.
  */
 class AnalysisDriver {
   /**
    * The task manager used to figure out how to compute analysis results.
    */
   final TaskManager taskManager;
@@ skipping 838 matching lines @@
   final TaskManager taskManager;
 
   _WorkOrderDependencyWalker(this.taskManager, WorkItem startingNode)
       : super(startingNode);
 
   @override
   WorkItem getNextInput(WorkItem node, List<WorkItem> skipInputs) {
     return node.gatherInputs(taskManager, skipInputs);
   }
 }