Grit: Fix Polymer bindings when there are multiple url()s

Also moving all Polymer binding related testing to a separate test in
html_inline_unittest.py, including a new test case for this bug.

Bug: 914591
Change-Id: I463ada044f827ad3ca31566391984b20a275e993
Reviewed-on: https://chromium-review.googlesource.com/c/1374955
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Reviewed-by: Dan Beam <dbeam@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#616932}
2 files changed