Remove NOTREACHED that gets hit for non well formed xhtml.

chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc

 // Copyright (c) 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/macros.h"
 #include "base/test/histogram_tester.h"
+#include "chrome/browser/page_load_metrics/metrics_web_contents_observer.h"
 #include "chrome/browser/page_load_metrics/observers/core_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/ui_test_utils.h"
 #include "net/test/embedded_test_server/embedded_test_server.h"
 
 class MetricsWebContentsObserverBrowserTest : public InProcessBrowserTest {
  public:
   MetricsWebContentsObserverBrowserTest() {}
@@ skipping 197 matching lines @@
   ASSERT_TRUE(embedded_test_server()->Start());
 
   ui_test_utils::NavigateToURL(
       browser(), embedded_test_server()->GetURL(
                      "/page_load_metrics/document_write_no_script.html"));
   NavigateToUntrackedUrl();
 
   histogram_tester_.ExpectTotalCount(
       internal::kHistogramDocWriteBlockParseStartToFirstContentfulPaint, 0);
 }
+
+IN_PROC_BROWSER_TEST_F(MetricsWebContentsObserverBrowserTest, BadXhtml) {
+  ASSERT_TRUE(embedded_test_server()->Start());
+
+  // 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
+  // for more.
+  ui_test_utils::NavigateToURL(
+      browser(),
+      embedded_test_server()->GetURL("/page_load_metrics/badxml.xhtml"));
+  NavigateToUntrackedUrl();
+
+  histogram_tester_.ExpectTotalCount(internal::kHistogramFirstLayout, 0);
+  histogram_tester_.ExpectTotalCount(internal::kHistogramFirstPaint, 0);
+  histogram_tester_.ExpectBucketCount(page_load_metrics::internal::kErrorEvents,
+                                      page_load_metrics::ERR_BAD_TIMING_IPC, 1);
+}