If PS2 (in CL2) depends on PS1 (in CL1), and if PS2 deletes a file that PS1 modified, PS2 fails to apply. See e.g. https://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_clobber_rel_ng/builds/145924/steps/bot_update/logs/patch%20error

DEBUG subprocess2( 215): git rm content/child/npapi/webplugin_ime_win.cc;  cwd=/b/build/slave/linux_clobber/build/src
Failed to apply patch for content/child/npapi/webplugin_ime_win.cc:
While running git rm content/child/npapi/webplugin_ime_win.cc;
  error: the following file has changes staged in the index:
      content/child/npapi/webplugin_ime_win.cc
  (use --cached to keep the file, or -f to force removal)


content/child/npapi/webplugin_ime_win.cc was modified by https://codereview.chromium.org/1815593002/#ps40001 and deleted by dependent patchset https://codereview.chromium.org/1813143002/#ps1


To avoid the problem I think either individual patchsets should be committed locally, or -f should be passed to git rm -f.
The latter is simpler, but could potentially miss conflicts (if the file was otherwise modified).