Adds macros to annotate variables and functions used from same thread or queue.

webrtc/base/task_queue.h

Index: webrtc/base/task_queue.h
diff --git a/webrtc/base/task_queue.h b/webrtc/base/task_queue.h
index dad4f431b7573f76d1d51a90b2cc2c53bf05c221..380dea70882424964b96c9022d77c1787842e751 100644
--- a/webrtc/base/task_queue.h
+++ b/webrtc/base/task_queue.h
@@ -155,7 +155,7 @@ static std::unique_ptr<QueuedTask> NewClosure(const Closure& closure,
 // TaskQueue itself has been deleted or it may happen synchronously while the
 // TaskQueue instance is being deleted.  This may vary from one OS to the next
 // so assumptions about lifetimes of pending tasks should not be made.
-class TaskQueue {
+class LOCKABLE TaskQueue {
  public:
   explicit TaskQueue(const char* queue_name);
   // TODO(tommi): Implement move semantics?