Buffer cross frame paint timing updates.

chrome/browser/page_load_metrics/page_load_metrics_embedder_interface.h

Index: chrome/browser/page_load_metrics/page_load_metrics_embedder_interface.h
diff --git a/chrome/browser/page_load_metrics/page_load_metrics_embedder_interface.h b/chrome/browser/page_load_metrics/page_load_metrics_embedder_interface.h
index 983a0145f03c158485914c621e799bb8c78986df..000fa2e57ff9d686207c62e87cb343e649b224f8 100644
--- a/chrome/browser/page_load_metrics/page_load_metrics_embedder_interface.h
+++ b/chrome/browser/page_load_metrics/page_load_metrics_embedder_interface.h
@@ -5,8 +5,14 @@
 #ifndef CHROME_BROWSER_PAGE_LOAD_METRICS_PAGE_LOAD_METRICS_EMBEDDER_INTERFACE_H_
 #define CHROME_BROWSER_PAGE_LOAD_METRICS_PAGE_LOAD_METRICS_EMBEDDER_INTERFACE_H_
 
+#include <memory>
+
 class GURL;
 
+namespace base {
+class Timer;
+}  // namespace base
+
 namespace page_load_metrics {
 
 class PageLoadTracker;
@@ -18,6 +24,7 @@ class PageLoadMetricsEmbedderInterface {
   virtual ~PageLoadMetricsEmbedderInterface() {}
   virtual bool IsNewTabPageUrl(const GURL& url) = 0;
   virtual void RegisterObservers(PageLoadTracker* metrics) = 0;
+  virtual std::unique_ptr<base::Timer> CreateTimer() = 0;
 };
 
 }  // namespace page_load_metrics