Added some browsertests to PageLoadMetrics change

chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc

Index: chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc
diff --git a/chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc b/chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc
index ac828737fc1ea3516a46a7e28b643036590887da..49e17132f8b4475c22de7d28702731709ca6c0a0 100644
--- a/chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc
+++ b/chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc
@@ -12,10 +12,11 @@ namespace page_load_metrics {
 class MetricsWebContentsObserverBrowserTest : public InProcessBrowserTest {
  public:
   const char* kHistogramNameFirstLayout =
-      "PageLoad.Timing.NavigationToFirstLayout";
+      "PageLoad.Timing2.NavigationToFirstLayout";
   const char* kHistogramNameDomContent =
-      "PageLoad.Timing.NavigationToDOMContentLoadedEventFired";
-  const char* kHistogramNameLoad = "PageLoad.Timing.NavigationToLoadEventFired";
+      "PageLoad.Timing2.NavigationToDOMContentLoadedEventFired";
+  const char* kHistogramNameLoad =
+      "PageLoad.Timing2.NavigationToLoadEventFired";
   MetricsWebContentsObserverBrowserTest() {};
   ~MetricsWebContentsObserverBrowserTest() override {};