Updated signature of ServerCache, as not all implementations will be able to

return a value they have locally cached.

PiperOrigin-RevId: 308092845

Author: amablue

database/src/desktop/persistence/in_memory_persistence_storage_engine.cc

@@ -76,7 +76,7 @@ void InMemoryPersistenceStorageEngine::RemoveAllUserWrites() {
   VerifyInTransaction();
 }
 
-const Variant& InMemoryPersistenceStorageEngine::ServerCache(const Path& path) {
+Variant InMemoryPersistenceStorageEngine::ServerCache(const Path& path) {
   return VariantGetChild(&server_cache_, path);
 }
 

database/src/desktop/persistence/in_memory_persistence_storage_engine.h

@@ -77,7 +77,7 @@ class InMemoryPersistenceStorageEngine : public PersistenceStorageEngine {
   //
   // @param path The path at which to load the data.
   // @return The data that was loaded.
-  const Variant& ServerCache(const Path& path) override;
+  Variant ServerCache(const Path& path) override;
 
   // Overwrite the server cache at the given path with the given data.
   //

database/src/desktop/persistence/persistence_storage_engine.h

@@ -133,7 +133,7 @@ class PersistenceStorageEngine {
   //
   // @param path The path at which to load the data.
   // @return The data that was loaded.
-  virtual const Variant& ServerCache(const Path& path) = 0;
+  virtual Variant ServerCache(const Path& path) = 0;
 
   // Overwrite the server cache at the given path with the given data.
   //