[Cleanup] Move all browsertests to use ScopedFeatureList to modify features

chrome/browser/page_load_metrics/observers/ads_page_load_metrics_observer.cc

Index: chrome/browser/page_load_metrics/observers/ads_page_load_metrics_observer.cc
diff --git a/chrome/browser/page_load_metrics/observers/ads_page_load_metrics_observer.cc b/chrome/browser/page_load_metrics/observers/ads_page_load_metrics_observer.cc
index a355a05a1c04f4ef68c733ecee81de4a89050da6..b1321ffb4b9a0d6efda2d20eaa0ace6113b060cc 100644
--- a/chrome/browser/page_load_metrics/observers/ads_page_load_metrics_observer.cc
+++ b/chrome/browser/page_load_metrics/observers/ads_page_load_metrics_observer.cc
@@ -12,6 +12,7 @@
 #include "base/memory/ptr_util.h"
 #include "base/strings/string_util.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_util.h"
+#include "chrome/common/chrome_features.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_contents.h"
@@ -19,8 +20,6 @@
 
 namespace {
 
-const base::Feature kAdsFeature{"AdsMetrics", base::FEATURE_ENABLED_BY_DEFAULT};
-
 bool FrameIsAd(content::NavigationHandle* navigation_handle) {
   // Because sub-resource filtering isn't always enabled, and doesn't work
   // well in monitoring mode (no CSS enforcement), it's difficult to identify
@@ -71,7 +70,7 @@ AdsPageLoadMetricsObserver::AdFrameData::AdFrameData(
 // static
 std::unique_ptr<AdsPageLoadMetricsObserver>
 AdsPageLoadMetricsObserver::CreateIfNeeded() {
-  if (!base::FeatureList::IsEnabled(kAdsFeature))
+  if (!base::FeatureList::IsEnabled(features::kAdsFeature))
     return nullptr;
   return base::MakeUnique<AdsPageLoadMetricsObserver>();
 }