Copy the passed in name string into the os_thread structure and delete it in the destructor.

runtime/vm/os_thread.h

Index: runtime/vm/os_thread.h
diff --git a/runtime/vm/os_thread.h b/runtime/vm/os_thread.h
index f01c4a2685c40a91d6e02e779760b215dd4c1554..9dbe50bd647208799aeec9318e2f8067a0de57b1 100644
--- a/runtime/vm/os_thread.h
+++ b/runtime/vm/os_thread.h
@@ -75,7 +75,8 @@ class OSThread : public BaseThread {
   void set_name(const char* name) {
     ASSERT(OSThread::Current() == this);
     ASSERT(name_ == NULL);
-    name_ = name;
+    ASSERT(name != NULL);
+    name_ = strdup(name);
   }
 
   Mutex* timeline_block_lock() const {
@@ -202,7 +203,7 @@ class OSThread : public BaseThread {
   const ThreadId id_;
   const ThreadId join_id_;
   const ThreadId trace_id_;  // Used to interface with tracing tools.
-  const char* name_;  // A name for this thread.
+  char* name_;  // A name for this thread.
 
   Mutex* timeline_block_lock_;
   TimelineEventBlock* timeline_block_;