drive: Merge 'persistent' and 'tmp' directories to 'files'

chrome/browser/chromeos/drive/drive.proto

Index: chrome/browser/chromeos/drive/drive.proto
diff --git a/chrome/browser/chromeos/drive/drive.proto b/chrome/browser/chromeos/drive/drive.proto
index 2f98714219925a46eb5db435d5bbbc8934bb3c70..1ea4ce3cb4aba1786fbf693d080248ace4512f4e 100644
--- a/chrome/browser/chromeos/drive/drive.proto
+++ b/chrome/browser/chromeos/drive/drive.proto
@@ -110,8 +110,6 @@ message ResourceMetadataHeader {
 }
 
 // Message to store information of an existing cache file.
-// Cache files are stored in 'tmp' or 'persistent' directory under the
-// root cache directory. See FileCache::GetCacheRootPath().
 message FileCacheEntry {
   // MD5 of the cache file. "local" if the file is locally modified.
   optional string md5 = 1;
@@ -128,8 +126,9 @@ message FileCacheEntry {
   // True if the file is a mounted archive file.
   optional bool is_mounted = 5;
 
+  // TODO(hashimoto): Remove this block after DB merge. crbug.com/234487
   // True if the file is in the persistent directory.
-  optional bool is_persistent = 6;
+  // optional bool is_persistent = 6;
 
   // When adding a new state, be sure to update TestFileCacheState and test
   // functions defined in drive_test_util.cc.