migrate from LockedPtr::getUniqueLock

Summary: The new name is `LockedPtr::as_lock`.

Reviewed By: aary

Differential Revision: D28987868

fbshipit-source-id: 8abd6a69a1b9c884adf137f06c24fe0df9ddd089

folly/logging/AsyncLogWriter.cpp

@@ -117,7 +117,7 @@ void AsyncLogWriter::flush() {
     messageReady_.notify_one();
 
     // Wait for notification from the I/O thread that it has done work.
-    ioCV_.wait(data.getUniqueLock());
+    ioCV_.wait(data.as_lock());
   }
 }
 
@@ -145,7 +145,7 @@ void AsyncLogWriter::ioThread() {
       ioQueue = data->getCurrentQueue();
       while (ioQueue->empty() && !(data->flags & FLAG_STOP)) {
         // Wait for a message or one of the above flags to be set.
-        messageReady_.wait(data.getUniqueLock());
+        messageReady_.wait(data.as_lock());
       }
 
       if (data->flags & FLAG_STOP) {
@@ -219,7 +219,7 @@ void AsyncLogWriter::stopIoThread(
     uint32_t extraFlags) {
   data->flags |= (FLAG_STOP | extraFlags);
   messageReady_.notify_one();
-  ioCV_.wait(data.getUniqueLock(), [&] {
+  ioCV_.wait(data.as_lock(), [&] {
     return bool(data->flags & FLAG_IO_THREAD_STOPPED);
   });