[Downloads] Handle externally deleted items

chrome/browser/android/download/download_manager_service.h

Index: chrome/browser/android/download/download_manager_service.h
diff --git a/chrome/browser/android/download/download_manager_service.h b/chrome/browser/android/download/download_manager_service.h
index 37b2b289952389e6fa0c6c3ad2c091d6617cd1ca..d585dd3ca15833b1288a79a197671f6069deadcf 100644
--- a/chrome/browser/android/download/download_manager_service.h
+++ b/chrome/browser/android/download/download_manager_service.h
@@ -73,6 +73,12 @@ class DownloadManagerService : public AllDownloadItemNotifier::Observer,
                        const JavaParamRef<jobject>& obj,
                        bool is_off_the_record);
 
+  // Called to check if the files associated with any downloads have been
+  // removed by an external action.
+  void CheckForExternallyRemovedDownloads(JNIEnv* env,
+                                          const JavaParamRef<jobject>& obj,
+                                          bool is_off_the_record);
+
   // DownloadHistory::Observer methods.
   void OnHistoryQueryComplete() override;