trace_event support for thread names

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 230d2099f7b92ed222333f794334e9f643150d1f..6b538f549d85abe34482d4e2c67ac99fbb230d32 100644
--- a/base/threading/platform_thread.h
+++ b/base/threading/platform_thread.h
@@ -74,9 +74,13 @@ class BASE_API PlatformThread {
   // Sleeps for the specified duration (units are milliseconds).
   static void Sleep(int duration_ms);
 
-  // Sets the thread name visible to a debugger.  This has no effect otherwise.
+  // Sets the thread name visible to debuggers/tools. This has no effect
+  // otherwise.

[Sigurður Ásgeirsson, 2011/08/04 12:31:39]

As you don't copy the name, I think you've added a requirement on this function
that the string must outlive the PlatformThread?

[nduca, 2011/08/04 18:17:38]

Actually, that's not the case --- the pointer here only goes into TLS, so its
inaccessible once the thread dies. And, we only retrieve the thread name when
called from that thread. 

The restriction is that the thread name has to survive for the duration of the
thread. I will clarify that.

   static void SetName(const char* name);
 
+  // Gets the thread name, if previously set by SetTName.

[Sigurður Ásgeirsson, 2011/08/04 12:31:39]

SetTName->SetName

[nduca, 2011/08/04 18:17:38]

Done.

+  static const char* GetName();
+
   // 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,