Enrich fileBrowserPrivate.onFileTransfersUpdated event to support displaying total number of jobs.

chrome/common/extensions/api/file_browser_private.idl

Index: chrome/common/extensions/api/file_browser_private.idl
diff --git a/chrome/common/extensions/api/file_browser_private.idl b/chrome/common/extensions/api/file_browser_private.idl
index 91e0d1cd3ede323e5671927fddef9bc6a4e0dc93..e06457624fe02098e2824d0e3e00dd86e7aaeb62 100644
--- a/chrome/common/extensions/api/file_browser_private.idl
+++ b/chrome/common/extensions/api/file_browser_private.idl
@@ -46,7 +46,7 @@ enum MountCompletedStatus {
 };
 
 // File transfer progress state.
-enum TransferState { started, in_progress, completed, failed };
+enum TransferState { added, started, in_progress, completed, failed };
 
 // Defines file transfer direction.
 enum TransferType { upload, download };
@@ -317,6 +317,9 @@ dictionary FileTransferStatus {
 
   // Approximated total size of transfer operation.
   double? total;
+
+  // Total number of jobs.
+  long num_total_jobs;
 };
 
 // Error during the drive sync.