Polygerrit now loads polymer-resin

polymer-resin intercepts polymer property assignments
before they reach XSS-vulnerable sinks like `href="..."`
and text nodes in `<script>` elements.

This follows the instructions in WORKSPACE for adding a new bower
dependency with kaspern's tweak to use the dependency in a rule so
that it's found.  //lib/js/bower_components.bzl has already been
rolled-back per those instructions.

The license is the polymer license as can be seen at
https://github.com/Polymer/polymer-resin/blob/master/LICENSE though
I'm not sure that //tools/js/bower2bazel.py recognizes it as such.

Docs for the added component are available at
https://github.com/Polymer/polymer-resin/blob/master/README.md
https://github.com/Polymer/polymer-resin/blob/master/getting-started.md

With this change, when I introduce an XSS vulnerability as below,
polymer-resin intercepts and stops it.

Patch that introduces a strawman vulnerability.

--- a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.js
+++ b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.js
@@ -55,6 +55,10 @@
         url: '/q/status:abandoned',
         name: 'Abandoned',
       },
+      {
+        url: location.hash.replace(/^#/, '') || 'http://example.com/#fragment_echoed_here',
+        name: 'XSS Me',
+      },
     ],
   }];

---

Address kaspern's and paladox's comments.

---

Undo version bumps for bower dependencies.

---

Change Soy index template to parallel app/index.html.

---

update polymer-resin to version 1.1.1-beta

----

Load polymer-resin into polygerrit-ui/**/*_test.html

After this, I ran the tests with
  -l chrome
  -l firefox

I ran a handful of tests with -p and observed that the
console shows "initResin" is called before test cases start
executing.

These changes were done programmaticly by running the script below
(approximately) thus:
```
gerrit/ $ cd polygerrit-ui/app
app/ $ find . -name \*test.html | xargs perl hack-tests.pl
```

```
use strict;

sub removeResin($) {
  my $s = $_[0];
  $s =~ s@<link rel="import" href="[^"]*/polymer-resin/[^"]*"[^>]*>\n?@@;
  $s =~ s@<script src="[^"]*/polymer-resin/[^"]*"></script>\n?@@;
  $s =~ s@<script>\s*security\.polymer_resin.*?</script>\n?@@s;
  return $s;
}

for my $f (@ARGV) {
  next if $f =~ m@/bower_components/|/node_modules/@;

  system('git', 'checkout', $f);
  print "$f\n";

  my @lines = ();
  open(IN, "<$f") or die "$f: $!";
  my $maxLineOfMatch = 0;
  while (<IN>) {
    push(@lines, $_);
    # Put a marker after core loading directives.
    $maxLineOfMatch = scalar(@lines)
      if m@/webcomponentsjs/|/polymer[.]html\b|/browser[.]js@;
  }
  close(IN) or die "$f: $!";

  die "$f missing loading directives" unless $maxLineOfMatch;

  # Given ./a/b/c/my_test.html, $pathToRoot is "../../.."
  # assuming no non-leading . or .. components in the path from find.
  my $pathToRoot = $f;
  $pathToRoot =~ s@^\.\/@@;
  $pathToRoot =~ s@^(.*?/)?app/@@;
  $pathToRoot =~ s@\/[^\/]*$@@;
  $pathToRoot =~ s@[^/]+@..@g;

  my $nLines = scalar(@lines);
  open(OUT, ">$f") or die "$f: $!";

  # Output the lines up to the last polymer-resin dependency
  # loaded explicitly by this test.
  my $before = join '', @lines[0..($maxLineOfMatch - 1)];
  $before = removeResin($before);
  print OUT "$before";

  # Dump out the lines that load polymer-resin and configure it for
  # polygerrit.
  if (1) {
      print OUT qq'<link rel="import" href="$pathToRoot/bower_components/polymer-resin/standalone/polymer-resin-debug.html"/>
<script>
security.polymer_resin.install({allowedIdentifierPrefixes: [\'\']});
</script>
    ';
  }

  # Emit any remaining lines.
  my $after = join '', @lines[$maxLineOfMatch..$#lines];
  $after = removeResin($after);
  $after =~ s/^\n*//;
  print OUT "$after";

  close(OUT) or die "$f: $!";
}
```

---

update polymer-resin to version 1.2.1-beta

---

update Soy index template to new style polymer-resin initialization

----

fix lint warnings

----

Load test/common-test-setup.html into *_test.html

Instead of inserting instructions to load and initialize polymer-resin into
every test file, add a common-test-setup.html that does that and also fold
iron-test-helpers loading into it.

----

imported files do not need to load webcomponentsjs

Change-Id: I71221c36ed8a0fe7f8720c1064a2fcc9555bb8df

lib/js/bower_components.bzl

@@ -167,6 +167,15 @@ def define_bower_components():
     license = "//lib:LICENSE-page.js",
     seed = True,
   )
+  bower_component(
+    name = "polymer-resin",
+    license = "//lib:LICENSE-polymer",
+    deps = [
+      ":polymer",
+      ":webcomponentsjs",
+    ],
+    seed = True,
+  )
   bower_component(
     name = "polymer",
     license = "//lib:LICENSE-polymer",