Introduce new constructor to PlatformThread.

webrtc/base/platform_thread.h

 /*
  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 14 matching lines @@
 
 // Compares two thread identifiers for equality.
 bool IsThreadRefEqual(const PlatformThreadRef& a, const PlatformThreadRef& b);
 
 // Sets the current thread name.
 void SetCurrentThreadName(const char* name);
 
 // Callback function that the spawned thread will enter once spawned.
 // A return value of false is interpreted as that the function has no
 // more work to do and that the thread can be released.
-typedef bool (*ThreadRunFunction)(void*);
+typedef bool (*ThreadRunFunctionDeprecated)(void*);
+typedef void (*ThreadRunFunction)(void*);
 
 enum ThreadPriority {
 #ifdef WEBRTC_WIN
   kLowPriority = THREAD_PRIORITY_BELOW_NORMAL,
   kNormalPriority = THREAD_PRIORITY_NORMAL,
   kHighPriority = THREAD_PRIORITY_ABOVE_NORMAL,
   kHighestPriority = THREAD_PRIORITY_HIGHEST,
   kRealtimePriority = THREAD_PRIORITY_TIME_CRITICAL
 #else
   kLowPriority = 1,
   kNormalPriority = 2,
   kHighPriority = 3,
   kHighestPriority = 4,
   kRealtimePriority = 5
 #endif
 };
 
 // Represents a simple worker thread.  The implementation must be assumed
 // to be single threaded, meaning that all methods of the class, must be
 // called from the same thread, including instantiation.
 class PlatformThread {
  public:
-  PlatformThread(ThreadRunFunction func, void* obj, const char* thread_name);
+  PlatformThread(ThreadRunFunctionDeprecated func,
+                 void* obj,
+                 const char* thread_name);
+  PlatformThread(ThreadRunFunction func,
+                 void* obj,
+                 const char* thread_name,
+                 ThreadPriority priority = kNormalPriority);
   virtual ~PlatformThread();
 
   const std::string& name() const { return name_; }
 
   // Spawns a thread and tries to set thread priority according to the priority
   // from when CreateThread was called.
   void Start();
 
   bool IsRunning() const;
 
   // Returns an identifier for the worker thread that can be used to do
   // thread checks.
   PlatformThreadRef GetThreadRef() const;
 
   // Stops (joins) the spawned thread.
   void Stop();
 
   // Set the priority of the thread. Must be called when thread is running.
+  // TODO(tommi): Make private and only allow public support via ctor.
   bool SetPriority(ThreadPriority priority);
 
  protected:
 #if defined(WEBRTC_WIN)
   // Exposed to derived classes to allow for special cases specific to Windows.
   bool QueueAPC(PAPCFUNC apc_function, ULONG_PTR data);
 #endif
 
  private:
   void Run();
 
-  ThreadRunFunction const run_function_;
+  ThreadRunFunctionDeprecated const run_function_deprecated_ = nullptr;
+  ThreadRunFunction const run_function_ = nullptr;
+  const ThreadPriority priority_ = kNormalPriority;
   void* const obj_;
   // TODO(pbos): Make sure call sites use string literals and update to a const
   // char* instead of a std::string.
   const std::string name_;
   rtc::ThreadChecker thread_checker_;
+  rtc::ThreadChecker worker_thread_checker_;

[the sun, 2017/02/22 13:42:57]

<bikeshed>
"worker_thread..." makes me associate it with the libjingle worker thread;
platform_thread_checker? spawned_thread_checker?
</bikeshed>

no big deal

[tommi, 2017/02/22 15:04:00]

Done. (went with spawned_thread_checker_)

 #if defined(WEBRTC_WIN)
   static DWORD WINAPI StartThread(void* param);
 
   bool stop_ = false;
   HANDLE thread_ = nullptr;
   DWORD thread_id_ = 0;
 #else
   static void* StartThread(void* param);
 
   // An atomic flag that we use to stop the thread. Only modified on the
   // controlling thread and checked on the worker thread.
   volatile int stop_flag_ = 0;
   pthread_t thread_ = 0;
 #endif  // defined(WEBRTC_WIN)
   RTC_DISALLOW_COPY_AND_ASSIGN(PlatformThread);
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_PLATFORM_THREAD_H_