When the download folder does not exist, change the download folder to a user's "Downloads"

base/path_service.cc

Index: base/path_service.cc
diff --git a/base/path_service.cc b/base/path_service.cc
index e72ae7deff9af69156ab2ed994de7431009ca5d8..2ad1af13b7141673a26f5724c9028ec16767127f 100644
--- a/base/path_service.cc
+++ b/base/path_service.cc
@@ -205,6 +205,10 @@ bool PathService::Get(int key, FilePath* result) {
   return true;
 }
 
+void PathService::Set(int key, const FilePath& path) {
+  AddToCache(key, path);
+}
+
 bool PathService::Override(int key, const FilePath& path) {
   PathData* path_data = GetPathData();
   DCHECK(path_data);