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

webrtc/base/thread.h

Index: webrtc/base/thread.h
diff --git a/webrtc/base/thread.h b/webrtc/base/thread.h
index 1a0c447264e4284e426b80e9cfd38a3a99503cba..1afe9d5ebef17aca78fb460a3d5df012a61bcaa5 100644
--- a/webrtc/base/thread.h
+++ b/webrtc/base/thread.h
@@ -93,7 +93,7 @@ class Runnable {
 
 // WARNING! SUBCLASSES MUST CALL Stop() IN THEIR DESTRUCTORS!  See ~Thread().
 
-class Thread : public MessageQueue {
+class LOCKABLE Thread : public MessageQueue {
  public:
   // Create a new Thread and optionally assign it to the passed SocketServer.
   Thread();