Add V8 bindings for Worker (Part I).

base/thread.h

Index: base/thread.h
===================================================================
--- base/thread.h	(revision 8350)
+++ base/thread.h	(working copy)
@@ -101,6 +101,9 @@
   // The native thread handle.
   PlatformThreadHandle thread_handle() { return thread_; }
 
+  // The thread ID.
+  int thread_id() const { return thread_id_; }
+
  protected:
   // Called just prior to starting the message loop
   virtual void Init() {}
@@ -130,7 +133,7 @@
   // by the created thread.
   MessageLoop* message_loop_;
 
-  // Our thread's ID.  Used for debugging purposes.
+  // Our thread's ID.
   int thread_id_;
 
   // The name of the thread.  Used for debugging purposes.