ContentStorageDirectImpl should return immediately if the #get(List) call is a
no-op.

PiperOrigin-RevId: 258789918
Change-Id: Ib90db382c90822966af71c05f1136675d363ba23
diff --git a/src/main/java/com/google/android/libraries/feed/feedstore/ContentStorageDirectImpl.java b/src/main/java/com/google/android/libraries/feed/feedstore/ContentStorageDirectImpl.java
index bdbca3d..9c3bf46 100644
--- a/src/main/java/com/google/android/libraries/feed/feedstore/ContentStorageDirectImpl.java
+++ b/src/main/java/com/google/android/libraries/feed/feedstore/ContentStorageDirectImpl.java
@@ -21,6 +21,7 @@
 import com.google.android.libraries.feed.common.Result;
 import com.google.android.libraries.feed.common.concurrent.MainThreadCaller;
 import com.google.android.libraries.feed.common.concurrent.MainThreadRunner;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 
@@ -43,6 +44,10 @@
 
   @Override
   public Result<Map<String, byte[]>> get(List<String> keys) {
+    if (keys.isEmpty()) {
+      return Result.success(Collections.emptyMap());
+    }
+
     return mainThreadCaller(
         LOCATION + "get", (consumer) -> contentStorage.get(keys, consumer), Result.failure());
   }