Change dialog texts for folder upload to explicitly indicate it's for 'Uploading'

ui/shell_dialogs/select_file_dialog.h

Index: ui/shell_dialogs/select_file_dialog.h
diff --git a/ui/shell_dialogs/select_file_dialog.h b/ui/shell_dialogs/select_file_dialog.h
index dc3c81333dc1d5ea794305d9e2c49494a20543a7..3bd3c8e11b4d4c33c79f52fc3c38c6ef6cd60630 100644
--- a/ui/shell_dialogs/select_file_dialog.h
+++ b/ui/shell_dialogs/select_file_dialog.h
@@ -31,9 +31,21 @@ class SHELL_DIALOGS_EXPORT SelectFileDialog
  public:
   enum Type {
     SELECT_NONE,
+
+    // For opening a folder.
     SELECT_FOLDER,
+
+    // Like SELECT_FOLDER, but the dialog UI should explicitly show it's
+    // specifically for "upload".
+    SELECT_UPLOAD_FOLDER,
+
+    // For saving into a file, allowing a nonexistent file to be selected.
     SELECT_SAVEAS_FILE,
+
+    // For opening a file.
     SELECT_OPEN_FILE,
+
+    // Like SELECT_OPEN_FILE, but allowing multiple files to open.
     SELECT_OPEN_MULTI_FILE
   };