[Page Load Metrics] Add mojom file to page load metrics.

chrome/renderer/page_load_metrics/page_timing_metrics_sender.h

Index: chrome/renderer/page_load_metrics/page_timing_metrics_sender.h
diff --git a/chrome/renderer/page_load_metrics/page_timing_metrics_sender.h b/chrome/renderer/page_load_metrics/page_timing_metrics_sender.h
index fc3fba1f51412bc22ab5a8d28e099db496ea333b..002272aa33586ddd4158a1244ff9c3655e056a65 100644
--- a/chrome/renderer/page_load_metrics/page_timing_metrics_sender.h
+++ b/chrome/renderer/page_load_metrics/page_timing_metrics_sender.h
@@ -29,11 +29,11 @@ class PageTimingMetricsSender {
   PageTimingMetricsSender(IPC::Sender* ipc_sender,
                           int routing_id,
                           std::unique_ptr<base::Timer> timer,
-                          const PageLoadTiming& initial_timing);
+                          mojo::StructPtr<PageLoadTiming> initial_timing);
   ~PageTimingMetricsSender();
 
   void DidObserveLoadingBehavior(blink::WebLoadingBehaviorFlag behavior);
-  void Send(const PageLoadTiming& timing);
+  void Send(mojo::StructPtr<PageLoadTiming> timing);
 
  protected:
   base::Timer* timer() const { return timer_.get(); }
@@ -45,7 +45,7 @@ class PageTimingMetricsSender {
   IPC::Sender* const ipc_sender_;
   const int routing_id_;
   std::unique_ptr<base::Timer> timer_;
-  PageLoadTiming last_timing_;
+  mojo::StructPtr<PageLoadTiming> last_timing_;
 
   // The the sender keep track of metadata as it comes in, because the sender is
   // scoped to a single committed load.