Revert 51858 - Disk cache: Switch the disk cache to use the cache_thread. ...

net/disk_cache/file_posix.cc

Index: net/disk_cache/file_posix.cc
===================================================================
--- net/disk_cache/file_posix.cc	(revision 51873)
+++ net/disk_cache/file_posix.cc	(working copy)
@@ -193,9 +193,6 @@
   io_list_.insert(operation.get());
   file->AddRef();  // Balanced on InvokeCallback()
 
-  if (!callback_thread_)
-      callback_thread_ = MessageLoop::current();
-
   WorkerPool::PostTask(FROM_HERE,
                        NewRunnableMethod(operation.get(), &BackgroundIO::Read),
                        true);
@@ -210,9 +207,6 @@
   io_list_.insert(operation.get());
   file->AddRef();  // Balanced on InvokeCallback()
 
-  if (!callback_thread_)
-    callback_thread_ = MessageLoop::current();
-
   WorkerPool::PostTask(FROM_HERE,
                        NewRunnableMethod(operation.get(), &BackgroundIO::Write,
                                          delete_buffer),
@@ -225,8 +219,6 @@
     IOList::iterator it = io_list_.begin();
     InvokeCallback(*it, true);
   }
-  // Unit tests can use different threads.
-  callback_thread_ = NULL;
 }
 
 // Runs on a worker thread.
@@ -380,9 +372,8 @@
 
 // Static.
 void File::WaitForPendingIO(int* num_pending_io) {
-  // We may be running unit tests so we should allow InFlightIO to reset the
-  // message loop.
-  Singleton<InFlightIO>::get()->WaitForPendingIO();
+  if (*num_pending_io)
+    Singleton<InFlightIO>::get()->WaitForPendingIO();
 }
 
 }  // namespace disk_cache