Adding UMA on page load size for pages with Media

chrome/browser/page_load_metrics/page_load_tracker.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/page_load_metrics/page_load_tracker.h"
 
 #include <algorithm>
 #include <ostream>
 #include <string>
 #include <utility>
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/user_metrics.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_embedder_interface.h"
 #include "chrome/browser/page_load_metrics/page_load_metrics_util.h"
 #include "chrome/common/page_load_metrics/page_load_timing.h"
 #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"
 
 // This macro invokes the specified method on each observer, passing the
 // variable length arguments as the method's arguments, and removes the observer
 // from the list of observers if the given method returns STOP_OBSERVING.
 #define INVOKE_AND_PRUNE_OBSERVERS(observers, Method, ...)    \
   for (auto it = observers.begin(); it != observers.end();) { \
     if ((*it)->Method(__VA_ARGS__) ==                         \
         PageLoadMetricsObserver::STOP_OBSERVING) {            \
@@ skipping 693 matching lines @@
   // explicitly filter these types of aborts out when deciding if the abort was
   // user initiated.
   if (page_end_reason != END_CLIENT_REDIRECT)
     page_end_user_initiated_info_ = user_initiated_info;
 
   if (is_certainly_browser_timestamp) {
     ClampBrowserTimestampIfInterProcessTimeTickSkew(&page_end_time_);
   }
 }
 
+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