Ignore download bytes in page load metrics.

chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc

 // 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.
 
 #include "base/command_line.h"
 #include "base/feature_list.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 1093 matching lines @@
   // navigation to another page.
   NavigateToUntrackedUrl();
 
   histogram_tester_.ExpectTotalCount(internal::kHistogramTotalBytes, 1);
 
   // Verify that there is a single sample recorded in the 10kB bucket (the size
   // of the main HTML response).
   histogram_tester_.ExpectBucketCount(internal::kHistogramTotalBytes, 10, 1);
 }
 
+IN_PROC_BROWSER_TEST_P(PageLoadMetricsBrowserTest,
+                       PayloadSizeIgnoresDownloads) {
+  ASSERT_TRUE(embedded_test_server()->Start());
+
+  bool prev_io_allowed = base::ThreadRestrictions::SetIOAllowed(true);
+  {
+    base::ScopedTempDir downloads_directory;
+    ASSERT_TRUE(downloads_directory.CreateUniqueTempDir());
+    browser()->profile()->GetPrefs()->SetFilePath(
+        prefs::kDownloadDefaultDirectory, downloads_directory.GetPath());
+    content::DownloadTestObserverTerminal downloads_observer(
+        content::BrowserContext::GetDownloadManager(browser()->profile()),
+        1,  // == wait_count (only waiting for "download-test1.lib").
+        content::DownloadTestObserver::ON_DANGEROUS_DOWNLOAD_FAIL);
+
+    ui_test_utils::NavigateToURL(
+        browser(), embedded_test_server()->GetURL(
+                       "/page_load_metrics/download_anchor_click.html"));
+    downloads_observer.WaitForFinished();
+  }
+  base::ThreadRestrictions::SetIOAllowed(prev_io_allowed);
+
+  NavigateToUntrackedUrl();
+
+  histogram_tester_.ExpectUniqueSample(internal::kHistogramTotalBytes, 0, 1);
+}
+
 INSTANTIATE_TEST_CASE_P(
     /* no prefix */,
     PageLoadMetricsBrowserTest,
     testing::Values(IPCType::LEGACY, IPCType::MOJO));