Implement GetResourceListInDirectoryByWapi.

chrome/browser/drive/drive_service_interface.h

Index: chrome/browser/drive/drive_service_interface.h
diff --git a/chrome/browser/drive/drive_service_interface.h b/chrome/browser/drive/drive_service_interface.h
index d9fa83e5b6b91359978bf302ea65b974c3c4b735..3df2938f6c9c7fee8384b9326b7f2fa9ded70cf8 100644
--- a/chrome/browser/drive/drive_service_interface.h
+++ b/chrome/browser/drive/drive_service_interface.h
@@ -364,6 +364,27 @@ class DriveServiceInterface {
       const std::string& resource_id,
       const std::string& app_id,
       const google_apis::AuthorizeAppCallback& callback) = 0;
+
+  // This is introduced as a temporary short term solution of the performance
+  // regression issue on Drive API v2.
+  //
+  // This fetches the resource list in a directory by usinig GData WAPI
+  // regardless of base protocol. In other words, even if we enabels Drive API
+  // v2, this method uses GData WAPI to fetch the resource list.
+  //
+  // |directory_resource_id| must not be empty.
+  // |callback| must not be null.
+  virtual google_apis::CancelCallback GetResourceListInDirectoryByWapi(
+      const std::string& directory_resource_id,
+      const google_apis::GetResourceListCallback& callback) = 0;
+
+  // GetResourceListInDirectoryByWapi can be paged. This method fetches the
+  // following pages.
+  //
+  // |callback| must not be null.
+  virtual google_apis::CancelCallback GetRemainingResourceList(
+      const GURL& next_url,
+      const google_apis::GetResourceListCallback& callback) = 0;
 };
 
 }  // namespace drive