Adding basic support for posting tasks to a process thread.

BUG=
R=magjed@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/41099004

Cr-Commit-Position: refs/heads/master@{#8614}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8614 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/utility/interface/process_thread.h

@@ -17,6 +17,14 @@
 namespace webrtc {
 class Module;
 
+class ProcessTask {
+ public:
+  ProcessTask() {}
+  virtual ~ProcessTask() {}
+
+  virtual void Run() = 0;
+};
+
 class ProcessThread {
  public:
   virtual ~ProcessThread();
@@ -36,6 +44,14 @@ class ProcessThread {
   // Can be called on any thread.
   virtual void WakeUp(Module* module) = 0;
 
+  // Queues a task object to run on the worker thread.  Ownership of the
+  // task object is transferred to the ProcessThread and the object will
+  // either be deleted after running on the worker thread, or on the
+  // construction thread of the ProcessThread instance, if the task did not
+  // get a chance to run (e.g. posting the task while shutting down or when
+  // the thread never runs).
+  virtual void PostTask(rtc::scoped_ptr<ProcessTask> task) = 0;
+
   // Adds a module that will start to receive callbacks on the worker thread.
   // Can be called from any thread.
   virtual void RegisterModule(Module* module) = 0;