Dropbox: changed reauthorization policy.

src/CloudProvider/Dropbox.cpp

@@ -42,6 +42,8 @@ IItem::Pointer Dropbox::rootDirectory() const {
   return make_unique<Item>("/", "", IItem::FileType::Directory);
 }
 
+bool Dropbox::reauthorize(int code) const { return code == 400 || code == 401; }
+
 ICloudProvider::GetItemDataRequest::Pointer Dropbox::getItemDataAsync(
     const std::string& id, GetItemDataCallback callback) {
   return make_unique<cloudstorage::GetItemDataRequest>(

src/CloudProvider/Dropbox.h

@@ -34,6 +34,7 @@ class Dropbox : public CloudProvider {
 
   std::string name() const;
   IItem::Pointer rootDirectory() const;
+  bool reauthorize(int code) const;
 
   GetItemDataRequest::Pointer getItemDataAsync(const std::string& id,
                                                GetItemDataCallback);