drive: Always use last_modified stored in ResourceEntry

chrome/browser/chromeos/drive/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 "chrome/browser/chromeos/drive/file_cache.h"
 
 #include <vector>
 
 #include "base/callback_helpers.h"
 #include "base/file_util.h"
@@ skipping 573 matching lines @@
   AssertOnSequencedWorkerPool();
 
   std::map<std::string, int>::iterator it = write_opened_files_.find(id);
   if (it == write_opened_files_.end())
     return;
 
   DCHECK_LT(0, it->second);
   --it->second;
   if (it->second == 0)
     write_opened_files_.erase(it);
+
+  // Update last modified date.
+  ResourceEntry entry;
+  FileError error = storage_->GetEntry(id, &entry);
+  if (error != FILE_ERROR_OK) {
+    LOG(ERROR) << "Failed to get entry: " << id << ", "
+               << FileErrorToString(error);
+    return;
+  }
+  entry.mutable_file_info()->set_last_modified(
+      base::Time::Now().ToInternalValue());
+  error = storage_->PutEntry(entry);
+  if (error != FILE_ERROR_OK) {
+    LOG(ERROR) << "Failed to put entry: " << id << ", "
+               << FileErrorToString(error);
+  }
 }
 
 }  // namespace internal
 }  // namespace drive