Make reprioritization IPC batch rather than per-request.

content/child/resource_dispatcher.h

 // Copyright (c) 2012 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.
 
 // See http://dev.chromium.org/developers/design-documents/multi-process-resource-loading
 
 #ifndef CONTENT_CHILD_RESOURCE_DISPATCHER_H_
 #define CONTENT_CHILD_RESOURCE_DISPATCHER_H_
 
 #include <stdint.h>
 
 #include <deque>
 #include <map>
 #include <memory>
 #include <string>
 
 #include "base/containers/hash_tables.h"
 #include "base/macros.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/shared_memory.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "base/time/time.h"
 #include "content/common/content_export.h"
+#include "content/common/resource_priority_change_info.h"
 #include "content/common/url_loader.mojom.h"
 #include "content/public/common/resource_type.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_sender.h"
 #include "net/base/request_priority.h"
 #include "third_party/WebKit/public/platform/WebURLRequest.h"
 #include "url/gurl.h"
 
 namespace mojo {
 class AssociatedGroup;
@@ skipping 157 matching lines @@
     // For mojo loading.
     mojom::URLLoaderAssociatedPtr url_loader;
     std::unique_ptr<mojom::URLLoaderClient> url_loader_client;
   };
   using PendingRequestMap = std::map<int, std::unique_ptr<PendingRequestInfo>>;
 
   // Helper to lookup the info based on the request_id.
   // May return NULL if the request as been canceled from the client side.
   PendingRequestInfo* GetPendingRequestInfo(int request_id);
 
+  // Priority change requests often come in batches, so store them in a
+  // queue and send them as a batch.
+  std::vector<ResourcePriorityChangeInfo> queued_priority_requests;
+
+  void DispatchPendingPriorityRequests();
+
   // Follows redirect, if any, for the given request.
   void FollowPendingRedirect(int request_id, PendingRequestInfo* request_info);
 
   // Message response handlers, called by the message handler for this process.
   void OnUploadProgress(int request_id, int64_t position, int64_t size);
   void OnReceivedResponse(int request_id, const ResourceResponseHead&);
   void OnReceivedCachedMetadata(int request_id, const std::vector<char>& data);
   void OnReceivedRedirect(int request_id,
                           const net::RedirectInfo& redirect_info,
                           const ResourceResponseHead& response_head);
@@ skipping 66 matching lines @@
   scoped_refptr<ResourceSchedulingFilter> resource_scheduling_filter_;
 
   base::WeakPtrFactory<ResourceDispatcher> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ResourceDispatcher);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_RESOURCE_DISPATCHER_H_