perf: we don't need to 'really' insert a preview when providing json

if we have intercepting 'image' when generating the json, then we
don't need to really insert the image into the server side TreeView
at all, we just need to provide it in the client json payload.

so we generate each bitmap once, and its base64 png representation
once.

Change-Id: I1b6916b036a0b84ef4346ebf2141240c4ae5b706
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/152675
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolan.mcnamara@collabora.com>

0 files changed, 0 insertions, 0 deletions