Remove MessageLoop::current() from url_request.cc.

net/url_request/url_request.cc

Index: net/url_request/url_request.cc
diff --git a/net/url_request/url_request.cc b/net/url_request/url_request.cc
index 26c3ac90ba4b1faae33026bf8dd53b63e121fed0..61308faafa8d04818411d808fa30329cb73ec569 100644
--- a/net/url_request/url_request.cc
+++ b/net/url_request/url_request.cc
@@ -12,12 +12,12 @@
 #include "base/compiler_specific.h"
 #include "base/lazy_instance.h"
 #include "base/memory/singleton.h"
-#include "base/message_loop/message_loop.h"
 #include "base/profiler/scoped_tracker.h"
 #include "base/rand_util.h"
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/synchronization/lock.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "base/values.h"
 #include "net/base/auth.h"
 #include "net/base/host_port_pair.h"
@@ -578,8 +578,7 @@ URLRequest::URLRequest(const GURL& url,
       received_response_content_length_(0),
       creation_time_(base::TimeTicks::Now()) {
   // Sanity check out environment.
-  DCHECK(base::MessageLoop::current())
-      << "The current base::MessageLoop must exist";
+  DCHECK(base::ThreadTaskRunnerHandle::IsSet());
 
   context->url_requests()->insert(this);
   net_log_.BeginEvent(NetLogEventType::REQUEST_ALIVE);