Add support for backgrounding processes on the Mac

base/process/process.h

 // Copyright (c) 2011 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 BASE_PROCESS_PROCESS_H_
 #define BASE_PROCESS_PROCESS_H_
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/move.h"
@@ skipping 89 matching lines @@
 
   // Waits for the process to exit. Returns true on success.
   // On POSIX, if the process has been signaled then |exit_code| is set to -1.
   // On Linux this must be a child process, however on Mac and Windows it can be
   // any process.
   bool WaitForExit(int* exit_code);
 
   // Same as WaitForExit() but only waits for up to |timeout|.
   bool WaitForExitWithTimeout(TimeDelta timeout, int* exit_code);
 
+#if defined(OS_MACOSX)
+  // The Mac needs a Mach port in order to manipulate a process's priority,
+  // and there's no good way to get that from base:: given the pid. These
+  // Mac variants of the IsProcessBackgrounded and SetProcessBackgrounded API
+  // take the Mach port for this reason. See crbug.com/460102
+  //
+  // A process is backgrounded when it's priority is lower than normal.
+  // Return true if the process with mach port |process_port| is backgrounded,
+  // false otherwise.
+  bool IsProcessBackgrounded(mach_port_t process_port) const;

[Robert Sesek, 2015/03/12 16:00:23]

naming: task_port, same in the comment, .cc file, and on line 126

[shrike, 2015/03/18 16:20:22]

Done.

+
+  // Set the process with the specified mach port as backgrounded. If value is
+  // true, the priority of the process will be lowered. If value is false, the
+  // priority of the process will be made "normal" - equivalent to default
+  // process priority. Returns true if the priority was changed, false
+  // otherwise.
+  bool SetProcessBackgrounded(mach_port_t process_port, bool value);
+#else
   // A process is backgrounded when it's priority is lower than normal.
   // Return true if this process is backgrounded, false otherwise.
   bool IsProcessBackgrounded() const;
 
   // Set a process as backgrounded. If value is true, the priority of the
   // process will be lowered. If value is false, the priority of the process
   // will be made "normal" - equivalent to default process priority.
   // Returns true if the priority was changed, false otherwise.
   bool SetProcessBackgrounded(bool value);
-
+#endif  // defined(OS_MACOSX)
   // Returns an integer representing the priority of a process. The meaning
   // of this value is OS dependent.
   int GetPriority() const;
 
  private:
 #if defined(OS_WIN)
   bool is_current_process_;
   win::ScopedHandle process_;
 #else
   ProcessHandle process_;
 #endif
 };
 
 }  // namespace base
 
 #endif  // BASE_PROCESS_PROCESS_H_