Revert "Add FirstInputDelay integration test"

This reverts commit 38d5e420.

Reason for revert:

Findit (https://goo.gl/kROfz5) identified CL at revision 743212 as the
culprit for flakes in the build cycles as shown on:
https://analysis.chromium.org/p/chromium/flake-portal/analysis/culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyQwsSDEZsYWtlQ3VscHJpdCIxY2hyb21pdW0vMzhkNWU0MjBmZTcyYzBiYjY2YzlmNzY4N2Q0NWU5MzhjNzdlMDBkZgw

Sample Failed Build: https://ci.chromium.org/b/8887906576420062352

Sample Failed Step: browser_tests

Sample Flaky Test: MetricIntegrationTest.FirstInputDelay

Original change's description:
> Add FirstInputDelay integration test
> 
> This CL adds a test for FID that tests equality between the JS value and
> the value reported in UKM and in UMA.
> 
> Change-Id: I00de8c947895700d86788ee4a95ea228458bb25f
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2067077
> Commit-Queue: Nicolás Peña Moreno <npm@chromium.org>
> Reviewed-by: Steve Kobes <skobes@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#743212}


Change-Id: I7eae1f24fb72da933586cb32b4b1cad24ade9844
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2067353
Cr-Commit-Position: refs/heads/master@{#743247}

chrome/browser/page_load_metrics/integration_tests/first_input_delay_browsertest.cc

-// Copyright 2020 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.
-
-#include "chrome/browser/page_load_metrics/integration_tests/metric_integration_test.h"
-
-#include "base/test/trace_event_analyzer.h"
-#include "chrome/test/base/ui_test_utils.h"
-#include "services/metrics/public/cpp/ukm_builders.h"
-
-using base::Bucket;
-using base::Value;
-using trace_analyzer::Query;
-using trace_analyzer::TraceAnalyzer;
-using trace_analyzer::TraceEventVector;
-using ukm::builders::PageLoad;
-
-IN_PROC_BROWSER_TEST_F(MetricIntegrationTest, FirstInputDelay) {
-  LoadHTML(R"HTML(
-    <script>
-    runtest = async () => {
-      const observePromise = new Promise(resolve => {
-        new PerformanceObserver(e => {
-          e.getEntries().forEach(entry => {
-            const fid = entry.processingStart - entry.startTime;
-            resolve(fid);
-          })
-        }).observe({type: 'first-input', buffered: true});
-      });
-      return await observePromise;
-    };
-    </script>
-  )HTML");
-
-  StartTracing({"loading"});
-
-  content::SimulateMouseClickAt(web_contents(), 0,
-                                blink::WebMouseEvent::Button::kLeft,
-                                gfx::Point(10, 10));
-
-  // Check web perf API.
-  double expected_fid = EvalJs(web_contents(), "runtest()").ExtractDouble();
-  EXPECT_GT(expected_fid, 0.0);
-
-  ui_test_utils::NavigateToURL(browser(), GURL("about:blank"));
-
-  // Check UKM.
-  ExpectUKMPageLoadMetric(PageLoad::kInteractiveTiming_FirstInputDelay4Name,
-                          expected_fid);
-
-  // Check UMA.
-  auto samples = histogram_tester().GetAllSamples(
-      "PageLoad.InteractiveTiming.FirstInputDelay4");
-  EXPECT_EQ(1ul, samples.size());
-  EXPECT_EQ(samples[0], Bucket(expected_fid, 1));
-}

chrome/browser/page_load_metrics/integration_tests/sources.gni

@@ -3,7 +3,6 @@
 # found in the LICENSE file.
 
 metric_integration_sources = [
-  "//chrome/browser/page_load_metrics/integration_tests/first_input_delay_browsertest.cc",
   "//chrome/browser/page_load_metrics/integration_tests/layout_instability_browsertest.cc",
   "//chrome/browser/page_load_metrics/integration_tests/metric_integration_test.cc",
   "//chrome/browser/page_load_metrics/integration_tests/metric_integration_test.h",