Revert of Remove calls to MessageLoop::current() in content.

content/child/child_process.cc

Index: content/child/child_process.cc
diff --git a/content/child/child_process.cc b/content/child/child_process.cc
index 9805c062f55c1872eb540abc0a029d8e32a72775..8411653ad8c2b699a8e1b5900b81d87d6c8d7b3d 100644
--- a/content/child/child_process.cc
+++ b/content/child/child_process.cc
@@ -10,7 +10,6 @@
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/process/process_handle.h"
-#include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread.h"
@@ -88,13 +87,13 @@
 
 void ChildProcess::AddRefProcess() {
   DCHECK(!main_thread_.get() ||  // null in unittests.
-         main_thread_->message_loop()->task_runner()->BelongsToCurrentThread());
+         base::MessageLoop::current() == main_thread_->message_loop());
   ref_count_++;
 }
 
 void ChildProcess::ReleaseProcess() {
   DCHECK(!main_thread_.get() ||  // null in unittests.
-         main_thread_->message_loop()->task_runner()->BelongsToCurrentThread());
+         base::MessageLoop::current() == main_thread_->message_loop());
   DCHECK(ref_count_);
   if (--ref_count_)
     return;