[fsp] Add support for providing thumbnails.

chrome/browser/chromeos/file_system_provider/operations/get_metadata.cc

Index: chrome/browser/chromeos/file_system_provider/operations/get_metadata.cc
diff --git a/chrome/browser/chromeos/file_system_provider/operations/get_metadata.cc b/chrome/browser/chromeos/file_system_provider/operations/get_metadata.cc
index 99a620b89c04de9ec0bd14ea90435237110c4743..c209e0c6bcca095527dcc9ad95985a79e8bc8b87 100644
--- a/chrome/browser/chromeos/file_system_provider/operations/get_metadata.cc
+++ b/chrome/browser/chromeos/file_system_provider/operations/get_metadata.cc
@@ -52,9 +52,11 @@ GetMetadata::GetMetadata(
     extensions::EventRouter* event_router,
     const ProvidedFileSystemInfo& file_system_info,
     const base::FilePath& entry_path,
+    ProvidedFileSystemInterface::MetadataFieldMask fields,
     const ProvidedFileSystemInterface::GetMetadataCallback& callback)
     : Operation(event_router, file_system_info),
       entry_path_(entry_path),
+      fields_(fields),
       callback_(callback) {
 }
 
@@ -64,6 +66,10 @@ GetMetadata::~GetMetadata() {
 bool GetMetadata::Execute(int request_id) {
   scoped_ptr<base::DictionaryValue> values(new base::DictionaryValue);
   values->SetString("entryPath", entry_path_.AsUTF8Unsafe());
+  values->SetBoolean(
+      "thumbnail",
+      (fields_ & ProvidedFileSystemInterface::METADATA_FIELD_THUMBNAIL) != 0);
+
   return SendEvent(
       request_id,
       extensions::api::file_system_provider::OnGetMetadataRequested::kEventName,