Make reprioritization IPC batch rather than per-request.

content/common/resource_priority_change_info.h

+// 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.
+
+#ifndef CONTENT_COMMON_RESOURCE_PRIORITY_CHANGE_INFO_H_
+#define CONTENT_COMMON_RESOURCE_PRIORITY_CHANGE_INFO_H_
+
+#include "content/common/content_export.h"
+#include "net/base/request_priority.h"
+
+namespace content {
+
+struct CONTENT_EXPORT ResourcePriorityChangeInfo {
+  ResourcePriorityChangeInfo();
+  ResourcePriorityChangeInfo(int request_id,
+                             net::RequestPriority priority,
+                             int intra_priority_value);
+  ~ResourcePriorityChangeInfo();
+
+  int request_id = -1;
+  net::RequestPriority priority = net::IDLE;
+  int intra_priority_value = 0;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_RESOURCE_PRIORITY_CHANGE_INFO_H_