Disable flaky PageLoadMetricsBrowserTest.BadXhtml on Linux dbg

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/files/scoped_temp_dir.h"
 #include "base/macros.h"
 #include "base/test/histogram_tester.h"
 #include "base/time/time.h"
 #include "chrome/browser/page_load_metrics/metrics_web_contents_observer.h"
 #include "chrome/browser/page_load_metrics/observers/aborts_page_load_metrics_observer.h"
@@ skipping 461 matching lines @@
   ui_test_utils::NavigateToURL(
       browser(), embedded_test_server()->GetURL(
                      "/page_load_metrics/document_write_no_script.html"));
   NavigateToUntrackedUrl();
 
   histogram_tester_.ExpectTotalCount(
       internal::kHistogramDocWriteBlockParseStartToFirstContentfulPaint, 0);
   histogram_tester_.ExpectTotalCount(internal::kHistogramDocWriteBlockCount, 0);
 }
 
-IN_PROC_BROWSER_TEST_F(PageLoadMetricsBrowserTest, BadXhtml) {
+// TODO(crbug.com/712935): Flaky on Linux dbg.
+#if defined(OS_LINUX) && !defined(NDEBUG)
+#define MAYBE_BadXhtml DISABLED_BadXhtml
+#else
+#define MAYBE_BadXhtml BadXhtml
+#endif
+IN_PROC_BROWSER_TEST_F(PageLoadMetricsBrowserTest, MAYBE_BadXhtml) {
   ASSERT_TRUE(embedded_test_server()->Start());
 
   scoped_refptr<TimingUpdatedObserver> timing_observer =
       CreateTimingUpdatedObserver();
   timing_observer->AddMatchingFields(TimingUpdatedObserver::FIRST_PAINT);
 
   // When an XHTML page contains invalid XML, it causes a paint of the error
   // message without a layout. Page load metrics currently treats this as an
   // error. Eventually, we'll fix this by special casing the handling of
   // documents with non-well-formed XML on the blink side. See crbug.com/627607
@@ skipping 284 matching lines @@
   ui_test_utils::NavigateToURL(browser(), embedded_test_server()->GetURL(
                                               "/page_load_metrics/large.html"));
   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);
 }