Convert base::MemoryMappedFile to use File instead of PlatformFile.

base/files/file_posix.cc

 // Copyright (c) 2012 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 "base/files/file.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <unistd.h>
@@ skipping 104 matching lines @@
   NOTIMPLEMENTED();  // NaCl doesn't implement flock struct.
   return File::FILE_ERROR_INVALID_OPERATION;
 }
 #endif  // defined(OS_NACL)
 
 }  // namespace
 
 // NaCl doesn't implement system calls to open files directly.
 #if !defined(OS_NACL)
 // TODO(erikkay): does it make sense to support FLAG_EXCLUSIVE_* here?
-void File::CreateBaseFileUnsafe(const FilePath& name, uint32 flags) {
+void File::InitializeUnsafe(const FilePath& name, uint32 flags) {
   base::ThreadRestrictions::AssertIOAllowed();
   DCHECK(!IsValid());
   DCHECK(!(flags & FLAG_ASYNC));
 
   int open_flags = 0;
   if (flags & FLAG_CREATE)
     open_flags = O_CREAT | O_EXCL;
 
   created_ = false;
 
@@ skipping 198 matching lines @@
 
 int File::WriteAtCurrentPosNoBestEffort(const char* data, int size) {
   base::ThreadRestrictions::AssertIOAllowed();
   DCHECK(IsValid());
   if (size < 0)
     return -1;
 
   return HANDLE_EINTR(write(file_, data, size));
 }
 
-bool File::Truncate(int64 length) {
+int64 File::GetLength() {
+  DCHECK(IsValid());
+
+  stat_wrapper_t file_info;
+  if (CallFstat(file_, &file_info))
+    return false;
+
+  return file_info.st_size;
+}
+
+bool File::SetLength(int64 length) {
   base::ThreadRestrictions::AssertIOAllowed();
   DCHECK(IsValid());
   return !CallFtruncate(file_, length);
 }
 
 bool File::Flush() {
   base::ThreadRestrictions::AssertIOAllowed();
   DCHECK(IsValid());
   return !CallFsync(file_);
 }
@@ skipping 106 matching lines @@
       return FILE_ERROR_FAILED;
   }
 }
 
 void File::SetPlatformFile(PlatformFile file) {
   DCHECK_EQ(file_, kInvalidPlatformFileValue);
   file_ = file;
 }
 
 }  // namespace base