Fix 15 coverity complaints....

net/disk_cache/mapped_file_posix.cc

 // Copyright (c) 2006-2008 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/disk_cache/mapped_file.h"
 
 #include <errno.h>
 #include <sys/mman.h>
 
 #include "base/logging.h"
 #include "net/disk_cache/disk_cache.h"
 
 namespace disk_cache {
 
-void* MappedFile::Init(const std::wstring name, size_t size) {
+void* MappedFile::Init(const std::wstring& name, size_t size) {
   DCHECK(!init_);
   if (init_ || !File::Init(name))
     return NULL;
 
   if (!size)
     size = GetLength();
 
   buffer_ = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED,
                  platform_file(), 0);
   init_ = true;
@@ skipping 19 matching lines @@
   size_t offset = block->offset() + view_size_;
   return Read(block->buffer(), block->size(), offset);
 }
 
 bool MappedFile::Store(const FileBlock* block) {
   size_t offset = block->offset() + view_size_;
   return Write(block->buffer(), block->size(), offset);
 }
 
 }  // namespace disk_cache