Add ability to retrieve a thread_name given a thread_id.

base/threading/platform_thread.h

Index: base/threading/platform_thread.h
diff --git a/base/threading/platform_thread.h b/base/threading/platform_thread.h
index 576695a4e7b5f8028f47cc5e02921b551ffb0a39..1760485d2da6db3c46e68235ba0769af3d935b87 100644
--- a/base/threading/platform_thread.h
+++ b/base/threading/platform_thread.h
@@ -76,6 +76,9 @@ class BASE_EXPORT PlatformThread {
   // Gets the thread name, if previously set by SetName.
   static const char* GetName();
 
+  // Gets the version number for the thread name.
+  static uint32 GetVersionForName();
+
   // Creates a new thread.  The |stack_size| parameter can be 0 to indicate
   // that the default stack size should be used.  Upon success,
   // |*thread_handle| will be assigned a handle to the newly created thread,