Add support for priorities in TaskQueue

webrtc/base/task_queue_win.cc

Index: webrtc/base/task_queue_win.cc
diff --git a/webrtc/base/task_queue_win.cc b/webrtc/base/task_queue_win.cc
index c8ef7211e895f8cffc47db8619ee1f35114349c2..73c0256b6cce5fecba5c45942c630a77e8a53921 100644
--- a/webrtc/base/task_queue_win.cc
+++ b/webrtc/base/task_queue_win.cc
@@ -49,6 +49,19 @@ void CALLBACK InitializeQueueThread(ULONG_PTR param) {
   ::TlsSetValue(GetQueuePtrTls(), data->thread_context);
   data->started->Set();
 }
+
+ThreadPriority TaskQueuePriorityToThreadPriority(TaskQueue::Priority priority) {
+  switch (priority) {
+    case TaskQueue::HIGH:
+      return kRealtimePriority;
+    case TaskQueue::LOW:
+      return kLowPriority;
+    case TaskQueue::NORMAL:
+    default:
+      break;
+  }
+  return kNormalPriority;
+}
 }  // namespace
 
 class TaskQueue::MultimediaTimer {
@@ -145,8 +158,11 @@ class TaskQueue::MultimediaTimer {
   RTC_DISALLOW_COPY_AND_ASSIGN(MultimediaTimer);
 };
 
-TaskQueue::TaskQueue(const char* queue_name)
-    : thread_(&TaskQueue::ThreadMain, this, queue_name) {
+TaskQueue::TaskQueue(const char* queue_name, Priority priority /*= NORMAL*/)
+    : thread_(&TaskQueue::ThreadMain,
+              this,
+              queue_name,
+              TaskQueuePriorityToThreadPriority(priority)) {
   RTC_DCHECK(queue_name);
   thread_.Start();
   Event event(false, false);