Add UMA that periodically logs number of outstanding requests

content/browser/loader/resource_dispatcher_host_impl.h

Index: content/browser/loader/resource_dispatcher_host_impl.h
diff --git a/content/browser/loader/resource_dispatcher_host_impl.h b/content/browser/loader/resource_dispatcher_host_impl.h
index 3f5aa959c691d7b6d091ec99a4a24a06c1ffc08a..181b84222c1ef4e92a614ac5ca0e399354eb59f2 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.h
+++ b/content/browser/loader/resource_dispatcher_host_impl.h
@@ -513,6 +513,10 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
   // Checks all pending requests and updates the load info if necessary.
   void UpdateLoadInfo();
 
+  // Records statistics about outstanding requests since the last call, and
+  // reset the stats.
+  void RecordOutstandingRequestsStats();
+
   // Resumes or cancels (if |cancel_requests| is true) any blocked requests.
   void ProcessBlockedRequestsForRoute(
       const GlobalFrameRoutingId& global_routing_id,
@@ -695,6 +699,10 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
       bool must_download,
       bool is_new_request);
 
+  // Returns true if there are two or more processes that are not network
+  // 2-quiet (i.e. have at least three outstanding requests).
+  bool HasRequestsFromMultipleActiveProcesses();
+
   LoaderMap pending_loaders_;
 
   // Collection of temp files downloaded for child processes via
@@ -710,6 +718,10 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
   // not empty and at least one RenderViewHost is loading.
   std::unique_ptr<base::RepeatingTimer> update_load_states_timer_;
 
+  // A timer that periodically calls RecordOutstandingRequestsStats.
+  std::unique_ptr<base::RepeatingTimer>
+      record_outstanding_requests_stats_timer_;
+
   // Request ID for browser initiated requests. request_ids generated by
   // child processes are counted up from 0, while browser created requests
   // start at -2 and go down from there. (We need to start at -2 because -1 is
@@ -763,6 +775,15 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
   // Largest number of outstanding requests seen so far in any single process.
   int largest_outstanding_request_per_process_count_seen_;
 
+  // Largest number of outstanding requests seen since the last call to
+  // RecordOutstandingRequestsStats.
+  int peak_outstanding_request_count_;
+
+  // Largest number of outstanding requests seen while there are outstanding
+  // requests from two or more processes, since the last call to
+  // RecordOutstandingRequestsStats.
+  int peak_outstanding_request_count_multitab_ = 0;
+
   // Time of the last user gesture. Stored so that we can add a load
   // flag to requests occurring soon after a gesture to indicate they
   // may be because of explicit user action.