[fsp] Move thumbnail logic to Drive specific C++ code.

chrome/browser/chromeos/extensions/file_manager/private_api_drive.cc

Index: chrome/browser/chromeos/extensions/file_manager/private_api_drive.cc
diff --git a/chrome/browser/chromeos/extensions/file_manager/private_api_drive.cc b/chrome/browser/chromeos/extensions/file_manager/private_api_drive.cc
index bd8d719d580bfa0678d5fb5d8be36fb8a2d4a8b5..2a15de30d0e7de40197de14295241bae8e9f1c1a 100644
--- a/chrome/browser/chromeos/extensions/file_manager/private_api_drive.cc
+++ b/chrome/browser/chromeos/extensions/file_manager/private_api_drive.cc
@@ -71,7 +71,10 @@ void FillDriveEntryPropertiesValue(const drive::ResourceEntry& entry_proto,
   const drive::FileSpecificInfo& file_specific_info =
       entry_proto.file_specific_info();
 
-  if (!entry_proto.resource_id().empty()) {
+  // The web thumbnail is used only when the file is not present. Otherwise
+  // it could be out of sync.
+  if (!entry_proto.resource_id().empty() &&
+      !file_specific_info.cache_state().is_present()) {
     properties->thumbnail_url.reset(
         new std::string("https://www.googledrive.com/thumb/" +
                         entry_proto.resource_id() + "?width=500&height=500"));