If you have a CL 'A' that modifies a file, and a dependent CL 'B' that removes the same file, then it is not possible to run a try job for 'B'.

What happens is that you see an error like this at the patch set:

===

While running git rm content/renderer/render_widget_fullscreen.cc;
  error: the following file has changes staged in the index:
      content/renderer/render_widget_fullscreen.cc
  (use --cached to keep the file, or -f to force removal)
Patch:  D    content/renderer/render_widget_fullscreen.cc
Index: content/renderer/render_widget_fullscreen.cc
diff --git a/content/renderer/render_widget_fullscreen.cc b/content/renderer/render_widget_fullscreen.cc
deleted file mode 100644