Use string for Histogram names since these are all ASCII anyway wide-characte...

net/base/file_stream_win.cc

 // Copyright (c) 2008 The Chromium Authors. All rights reserved.  Use of this
 // source code is governed by a BSD-style license that can be found in the
 // LICENSE file.
 
 #include "net/base/file_stream.h"
 
 #include <windows.h>
 
 #include "base/logging.h"
 #include "base/message_loop.h"
@@ skipping 60 matching lines @@
 
 FileStream::AsyncContext::~AsyncContext() {
   bool waited = false;
   base::Time start = base::Time::Now();
   while (callback_) {
     waited = true;
     MessageLoopForIO::current()->WaitForIOCompletion(INFINITE, this);
   }
   if (waited) {
     // We want to see if we block the message loop for too long.
-    UMA_HISTOGRAM_TIMES(L"AsyncIO.FileStreamClose", base::Time::Now() - start);
+    UMA_HISTOGRAM_TIMES("AsyncIO.FileStreamClose", base::Time::Now() - start);
   }
 }
 
 void FileStream::AsyncContext::IOCompletionIsPending(
     CompletionCallback* callback) {
   DCHECK(!callback_);
   callback_ = callback;
 }
 
 void FileStream::AsyncContext::OnIOCompleted(
@@ skipping 189 matching lines @@
   } else if (overlapped) {
     async_context_->IOCompletionIsPending(callback);
     rv = ERR_IO_PENDING;
   } else {
     rv = static_cast<int>(bytes_written);
   }
   return rv;
 }
 
 }  // namespace net
-