navigation from directory table to source location does not work with "genhtml --frames"

[henry2cox]

Moving this from the discussion in PR #161. The PR is about something totally different - and I don't want this one to be lost.

• Background:
  * ‘genhtml –frames’ option causes us to generate a sourceview page with a colorized/clickable PNG image on the left of the source code.
  This can be quite convenient for finding stuff in moderate sized files.
  * We also have a rather new feature which adds href links from entries in the summary table to the first line in the source code in the corresponding category – for example, from the count of unexercised lines in the fileview summary table to the first unexercised line in the file.
  (Please see the genhtml man page for the “--show-navigation” option.)

• The problem:
  * I wanted to have similar hrefs from the “directory view” table entries to the corresponding sourceview line – for example, to be able to click on the “unexercised line” count in in the row corresponding to file “foo.c” and be taken to the first unexercised line in the foo.c sourceview.
  This saves at least one click and one mouse movement – and is pretty commonly done when tracking down and diagnosing coverage issues.
  * This works fine if we do not use frames – but fails if we do use frames.
  “works fine” means that the href does what I want (for both chrome and firefox, at least).
  “fails” means that the href does not take me anywhere (like a dead link to nowhere). It fails for both chrome and firefox – but fails slightly differently for each of them.
  * Some doc that I found suggests that this ought to work with frames…but that frames are somewhat orphaned and not well supported by anyone ☹

• The question:
  * Does anyone know how to fix this such that the links will work correctly with frames?
  Or, is there a better way to achieve a frames-like look and feel, which will also work with href navigation. One restriction is that I think we need to do this with static HTML – no active pages.