Adding UMA on page load size for pages with Media

chrome/browser/page_load_metrics/page_load_tracker.cc

Index: chrome/browser/page_load_metrics/page_load_tracker.cc
diff --git a/chrome/browser/page_load_metrics/page_load_tracker.cc b/chrome/browser/page_load_metrics/page_load_tracker.cc
index aff76c3883f8488d590aed1e93dcc77e4bc6a0c1..dfccbaf83602e53513401b99fe705567cf578d61 100644
--- a/chrome/browser/page_load_metrics/page_load_tracker.cc
+++ b/chrome/browser/page_load_metrics/page_load_tracker.cc
@@ -19,6 +19,7 @@
 #include "content/public/browser/navigation_details.h"
 #include "content/public/browser/navigation_handle.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_observer.h"
 #include "content/public/common/browser_side_navigation_policy.h"
 #include "ui/base/page_transition_types.h"
 
@@ -732,4 +733,11 @@ void PageLoadTracker::UpdatePageEndInternal(
   }
 }
 
+void PageLoadTracker::MediaStartedPlaying(
+    const content::WebContentsObserver::MediaPlayerInfo& video_type,
+    bool is_in_main_frame) {
+  for (const auto& observer : observers_)
+    observer->MediaStartedPlaying(video_type, is_in_main_frame);
+}
+
 }  // namespace page_load_metrics