Fixed the bug that Drive doesn't appear on Files App on epehmeral mode.

components/drive/chromeos/file_cache.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 "components/drive/chromeos/file_cache.h"
 
 #include <linux/fs.h>
 #include <sys/ioctl.h>
 #include <sys/xattr.h>
 
@@ skipping 76 matching lines @@
   FileAttributes flags = 0;
   if (ioctl(file.GetPlatformFile(), FS_IOC_GETFLAGS, &flags) < 0) {
     PLOG(ERROR) << "ioctl: " << path.value();
     return -1;
   }
   return flags;
 }
 
 // Marks the cache file to be removable by cryptohome.
 bool SetRemovable(const base::FilePath& path) {
+  // TODO(oka): This function always returns true as a quick fix for
+  // http://crbug.com/650268. Remove the hack by immediately returning true if
+  // underlying file system doesn't support file attributes, as tmpfs for
+  // ephemeral mode.
   FileAttributes flags = GetFileAttributes(path);
-  if (flags < 0) return false;
+  if (flags < 0) {
+    // TODO(oka): false should be returned.

[hashimoto, 2016/10/13 06:12:06]

This can result in ignoring real errors and this sounds scary to me.
As fukino@ said, can't you change the behavior only on file systems which don't
support attributes?
For example, by using statfs
(http://stackoverflow.com/questions/26635846/how-to-tell-if-a-file-is-on-tmpfs...),
or by checking errno after xattr to see if it's ENOTSUP.

[oka, 2016/10/14 02:36:43]

Done.

Thank you. I used xattr.

+    return true;
+  }
   if ((flags & FS_NODUMP_FL) == FS_NODUMP_FL) return true;
 
-  return SetFileAttributes(path, flags | FS_NODUMP_FL);
+  SetFileAttributes(path, flags | FS_NODUMP_FL);
+  // TODO(oka): Return value of the above method should be returned.
+  return true;
 }
 
 // Marks the cache file to be unremovable by cryptohome.
 bool UnsetRemovable(const base::FilePath& path) {
+  // TODO(oka): This function always returns true as a quick fix for
+  // http://crbug.com/650268. Remove the hack by immediately returning true if
+  // underlying file system doesn't support file attributes, as tmpfs for
+  // ephemeral mode.
   FileAttributes flags = GetFileAttributes(path);
-  if (flags < 0) return false;
+  if (flags < 0) {
+    // TODO(oka): false should be returned.
+    return true;
+  }
   if ((flags & FS_NODUMP_FL) == 0) return true;
 
-  return SetFileAttributes(path, flags & ~FS_NODUMP_FL);
+  SetFileAttributes(path, flags & ~FS_NODUMP_FL);
+  // TODO(oka): Return value of the above method should be returned.
+  return true;
 }
 
 // Marks |path| as drive cache dir.
 // Returns if the operation succeeded.
 bool MarkAsDriveCacheDir(const base::FilePath& path) {
   return SetRemovable(path)
       && SetExtendedFileAttributes(path, FileCache::kGCacheFilesAttribute, "");
 }
 
 class CacheInfoLatestCompare {
@@ skipping 521 matching lines @@
   }
   if (it->HasError())
     return false;
 
   if (!RenameCacheFilesToNewFormat())
     return false;
 
   // Run this every time to resolve inconsistency between metadata
   // and file attributes which possibly occurs on abrupt power failure.
   if (!FixMetadataAndFileAttributes()) {
-    return false;
+    // Returning true as a quick fix for http://crbug.com/650268.
+    // TODO(oka): We should avoid to call the method if the underlying
+    // filesystem does not support file attributes, as tmpfs for ephemeral mode.
+    return true;
   }
 
   return true;
 }
 
 void FileCache::Destroy() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   in_shutdown_.Set();
 
@@ skipping 242 matching lines @@
 
 bool FileCache::IsEvictable(const std::string& id, const ResourceEntry& entry) {
   return IsPresent(entry) &&
          !entry.file_specific_info().cache_state().is_pinned() &&
          !entry.file_specific_info().cache_state().is_dirty() &&
          !mounted_files_.count(id);
 }
 
 }  // namespace internal
 }  // namespace drive