Remove dead 'sizes' parsing code in chrome/renderer/web_apps.cc

It looks like the code in question uses WebIconSizesParser - which
provide the same functionality. Remove the code and transplant relevant
(non-duplicate) tests to WebIconSizesParserTest.

Change-Id: I7b7c4e0140268eddccf858174ee6fd78395a0010
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1545051
Commit-Queue: Jochen Eisinger <jochen@chromium.org>
Auto-Submit: Fredrik Söderquist <fs@opera.com>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#646010}
4 files changed