[tools] delete profile_startup.dart (#3703)

The same can now be achieved using `flutter run --trace-startup --no-checked`.

dev/tools/profile_startup.dart

-#!/usr/bin/env dart
-// Copyright 2015 The Chromium Authors. 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:async';
-import 'dart:convert';
-import 'dart:io';
-
-const int ITERATIONS = 5;
-
-String runWithLoggingSync(List<String> cmd, {
-  bool checked: true,
-  String workingDirectory
-}) {
-  ProcessResult results =
-      Process.runSync(cmd[0], cmd.getRange(1, cmd.length).toList(), workingDirectory: workingDirectory);
-  if (results.exitCode != 0) {
-    String errorDescription = 'Error code ${results.exitCode} '
-        'returned when attempting to run command: ${cmd.join(' ')}';
-    print(errorDescription);
-    if (results.stderr.length > 0)
-      print('Errors logged: ${results.stderr.trim()}');
-    if (checked)
-      throw errorDescription;
-  }
-  if (results.stdout.trim().isNotEmpty)
-    print(results.stdout.trim());
-  return results.stdout;
-}
-
-double timeToFirstFrame(trace) {
-  // TODO(eseidel): Sort! Events are not guarenteed to be in timestamp order.
-  List events = trace['traceEvents'];
-  int firstTimeStamp = events[0]['ts'].toInt();
-  var firstSwap = events.firstWhere((e) => e['name'] == 'NativeViewGLSurfaceEGL:RealSwapBuffers');
-  int swapStart = firstSwap['ts'].toInt();
-  int swapEnd = swapStart + firstSwap['dur'].toInt();
-  return (swapEnd - firstTimeStamp) / 1000; // microseconds to milliseconds.
-}
-
-Future<double> test(String tracesDir, String projectPath, int runNumber) async {
-  // If we used package:path we could grab the basename of project_path
-  // and include that in the trace_name.
-  String tracePath = "${tracesDir}/trace_$runNumber.json";
-  runWithLoggingSync([
-    'flutter',
-    'run',
-    '--no-checked',
-    '--trace-startup'
-  ], workingDirectory: projectPath);
-  await new Future.delayed(const Duration(seconds: 2), () => "");
-  runWithLoggingSync([
-    'flutter',
-    'trace',
-    '--stop',
-    '--out=${tracePath}'
-  ], workingDirectory: projectPath);
-
-  JsonDecoder decoder = new JsonDecoder();
-  String contents = await new File(tracePath).readAsString();
-  Map data = await decoder.convert(contents);
-  return timeToFirstFrame(data);
-}
-
-// package:statistics has slightly nicer ones of these.
-double mean(List<double> times) {
-  return times.reduce((a,b) => a + b) / times.length;
-}
-
-double median(List<double> times) {
-  times.sort();
-  return times[times.length ~/ 2];
-}
-
-main(List<String> args) async {
-  // We could do much more sophisticated things if we used package:args.
-  if (args.length < 1) {
-    print("Usage: profile_startup.dart PROJECT_PATH\n");
-    print("PROJECT_PATH required.");
-    return 1;
-  }
-  String projectPath = args[0];
-  String traces_dir = '/tmp';
-
-  List<double> times = [];
-  print("Profiling startup using flutter run --trace-startup.");
-  print("Measuring from first trace event to completion of first frame upload.");
-  print("aka NativeViewGLSurfaceEGL:RealSwapBuffers.\n");
-  print("NOTE: If device is not on/unlocked tracing may fail.\n");
-
-  print("$ITERATIONS runs using $projectPath:");
-  for (var x = 0; x < ITERATIONS; x++) {
-    int runNumber = x + 1;
-    double time = await test(traces_dir, projectPath, runNumber);
-    print(" ${runNumber.toString().padLeft(2)} $time");
-    times.add(time);
-  }
-  print("mean: ${mean(times)}");
-  print("median: ${median(times)}");
-}