Make reprioritization IPC batch rather than per-request.

content/browser/loader/resource_dispatcher_host_impl.cc

Index: content/browser/loader/resource_dispatcher_host_impl.cc
diff --git a/content/browser/loader/resource_dispatcher_host_impl.cc b/content/browser/loader/resource_dispatcher_host_impl.cc
index fad7d214783f44ff611a9918f0859c664bbd2166..149d9a6440d311a6076561da59fd700841001686 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.cc
+++ b/content/browser/loader/resource_dispatcher_host_impl.cc
@@ -1774,17 +1774,22 @@ void ResourceDispatcherHostImpl::OnReleaseDownloadedFile(
 
 void ResourceDispatcherHostImpl::OnDidChangePriority(
     ResourceRequesterInfo* requester_info,
-    int request_id,
-    net::RequestPriority new_priority,
-    int intra_priority_value) {
-  ResourceLoader* loader = GetLoader(requester_info->child_id(), request_id);
-  // The request may go away before processing this message, so |loader| can
-  // legitimately be null.
-  if (!loader)
-    return;
+    const std::vector<ResourcePriorityChangeInfo>& priority_info_vector) {
+  std::vector<ResourceScheduler::PriorityChangeRequest>
+      priority_change_requests;
+
+  for (auto& v : priority_info_vector) {
+    ResourceLoader* loader =
+        GetLoader(requester_info->child_id(), v.request_id);
+    // The request may go away before processing this message, so |loader| can
+    // legitimately be null.
+    if (!loader)
+      continue;
 
-  scheduler_->ReprioritizeRequest(loader->request(), new_priority,
-                                  intra_priority_value);
+    priority_change_requests.push_back(
+        {loader->request(), v.priority, v.intra_priority_value});
+  }
+  scheduler_->ReprioritizeRequests(priority_change_requests);
 }
 
 void ResourceDispatcherHostImpl::RegisterDownloadedTempFile(