Fix error handling in POSIX version of the base::File::GetLength.

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 <stdint.h>
 #include <sys/stat.h>
@@ skipping 303 matching lines @@
   return HANDLE_EINTR(write(file_.get(), data, size));
 }
 
 int64_t File::GetLength() {
   DCHECK(IsValid());
 
   SCOPED_FILE_TRACE("GetLength");
 
   stat_wrapper_t file_info;
   if (CallFstat(file_.get(), &file_info))
-    return false;
+    return -1;
 
   return file_info.st_size;
 }
 
 bool File::SetLength(int64_t length) {
   ThreadRestrictions::AssertIOAllowed();
   DCHECK(IsValid());
 
   SCOPED_FILE_TRACE_WITH_SIZE("SetLength", length);
   return !CallFtruncate(file_.get(), length);
@@ skipping 190 matching lines @@
   return !HANDLE_EINTR(fsync(file_.get()));
 #endif
 }
 
 void File::SetPlatformFile(PlatformFile file) {
   DCHECK(!file_.is_valid());
   file_.reset(file);
 }
 
 }  // namespace base