Removes user-metrics-perf.js layout test

This removes the user-metrics-perf.js layout test in preference to the
end-to-end test in the DevTools repo, created in this CL:
https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2084582

Bug: 1032561, 1046784
Change-Id: Iebe9baf872302579af89cea3542e343c9681a185
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2084557Reviewed-by: Tim van der Lippe <tvanderlippe@chromium.org>
Commit-Queue: Paul Lewis <aerotwist@chromium.org>
Cr-Commit-Position: refs/heads/master@{#746416}

third_party/blink/web_tests/http/tests/devtools/user-metrics-perf-expected.txt

-Tests list of user metrics performance codes and invocations.
-
-recordPanelLoaded:
-Performance mark: DevTools.Launch.Console
-Performance histogram: DevTools.Launch.Console - positive duration?: true
-Performance mark: DevTools.Launch.Elements
-Performance histogram: DevTools.Launch.Elements - positive duration?: true
-Performance mark: DevTools.Launch.Network
-Performance histogram: DevTools.Launch.Network - positive duration?: true
-Performance mark: DevTools.Launch.Sources
-Performance histogram: DevTools.Launch.Sources - positive duration?: true
-
-Test that loading the tool only triggers the marker:
-Performance mark: DevTools.Launch.Console
-Performance mark: DevTools.Launch.Elements
-Performance mark: DevTools.Launch.Network
-Performance mark: DevTools.Launch.Sources
-

third_party/blink/web_tests/http/tests/devtools/user-metrics-perf.js

-// Copyright 2017 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.
-
-(async function() {
-  TestRunner.addResult(`Tests list of user metrics performance codes and invocations.\n`);
-
-  const testHistogramRecording = (panel, histogram, expectHistogram, testExecutor) => {
-    let recordHistogramComplete;
-    performance.mark = function(name) {
-      TestRunner.addResult(`Performance mark: ${name}`);
-      if (!expectHistogram)
-        recordHistogramComplete();
-    };
-    InspectorFrontendHost.recordPerformanceHistogram = function(name, duration) {
-      TestRunner.addResult(`Performance histogram: ${name} - positive duration?: ${duration > 0}`);
-      recordHistogramComplete();
-    };
-
-    return new Promise((resolve, reject) => {
-      Host.userMetrics._firedLaunchHistogram = undefined;
-      Host.userMetrics.setLaunchPanel(panel);
-      testExecutor(panel, histogram);
-      recordHistogramComplete = resolve;
-    });
-  };
-
-  const testPanelLoaded = (panel, histogram) =>
-      testHistogramRecording(panel, histogram, true, Host.userMetrics.panelLoaded.bind(Host.userMetrics));
-
-  const testShowView = (panel, histogram) =>
-      testHistogramRecording(panel, histogram, false, UI.viewManager.showView.bind(UI.viewManager));
-
-  TestRunner.addResult('recordPanelLoaded:');
-  await testPanelLoaded('console', 'DevTools.Launch.Console');
-  await testPanelLoaded('elements', 'DevTools.Launch.Elements');
-  await testPanelLoaded('network', 'DevTools.Launch.Network');
-  await testPanelLoaded('sources', 'DevTools.Launch.Sources');
-
-  TestRunner.addResult('\nTest that loading the tool only triggers the marker:');
-  await testShowView('console', 'DevTools.Launch.Console');
-  await testShowView('elements', 'DevTools.Launch.Elements');
-  await testShowView('network', 'DevTools.Launch.Network');
-  await testShowView('sources', 'DevTools.Launch.Sources');
-
-  TestRunner.completeTest();
-})();