base: Fix DCHECK when thread creation fails

base/message_loop/message_loop.cc

Index: base/message_loop/message_loop.cc
diff --git a/base/message_loop/message_loop.cc b/base/message_loop/message_loop.cc
index cfa86d98ce4351137eb9d222af17ed5e7fc30780..13bc854b038c5990cbc94f7ca07a94435717a65a 100644
--- a/base/message_loop/message_loop.cc
+++ b/base/message_loop/message_loop.cc
@@ -133,9 +133,11 @@ MessageLoop::MessageLoop(scoped_ptr<MessagePump> pump)
 }
 
 MessageLoop::~MessageLoop() {
-  // current() could be NULL if this message loop is destructed before it is
-  // bound to a thread.
-  DCHECK(current() == this || !current());
+  // If |pump_| is non-null, this message loop has been bound and should be the
+  // current one on this thread. Otherwise, this loop is being destructed before
+  // it was bound to a thread, so a different message loop (or no loop at all)
+  // may be current.
+  DCHECK((pump_ && current() == this) || (!pump_ && current() != this));
 
   // iOS just attaches to the loop, it doesn't Run it.
   // TODO(stuartmorgan): Consider wiring up a Detach().
@@ -177,7 +179,8 @@ MessageLoop::~MessageLoop() {
   task_runner_ = NULL;
 
   // OK, now make it so that no one can find us.
-  lazy_tls_ptr.Pointer()->Set(NULL);
+  if (current() == this)
+    lazy_tls_ptr.Pointer()->Set(nullptr);
 }
 
 // static