Step 2 in porting disk cache to using FilePath.

net/disk_cache/mapped_file_posix.cc

Index: net/disk_cache/mapped_file_posix.cc
diff --git a/net/disk_cache/mapped_file_posix.cc b/net/disk_cache/mapped_file_posix.cc
index a28a7d4370a3b6314a05096f9ab68fe120181a8f..6370ca613674c21de4d9a24be5e0da9cfa9a21f2 100644
--- a/net/disk_cache/mapped_file_posix.cc
+++ b/net/disk_cache/mapped_file_posix.cc
@@ -7,6 +7,7 @@
 #include <errno.h>
 #include <sys/mman.h>
 
+#include "base/file_path.h"
 #include "base/logging.h"
 #include "net/disk_cache/disk_cache.h"
 
@@ -14,7 +15,7 @@ namespace disk_cache {
 
 void* MappedFile::Init(const std::wstring& name, size_t size) {
   DCHECK(!init_);
-  if (init_ || !File::Init(name))
+  if (init_ || !File::Init(FilePath::FromWStringHack(name)))
     return NULL;
 
   if (!size)