WebUI: Remove defunct PolymerTest.testIronIcons method

This method is using /deep/ which only worked in Shadow DOM v0. WebUI has
been using SDv1 since M72, and this test is silently doing nothing (does not
find any iron-icons to assert on).

Moreover, running additional checks after every test is a questionable
pattern.
 - The state of the DOM is not necessarily valid/useful at the end
   of a unit test (see workaround removed in site_details_permission_test.js).
 - Such checks often confuse developers by throwing an error only if another
   error has happened earlier (which affects the DOM state).
 - Given that these tests are silently injected by the PolymerTest base class
   developers often are not aware that these checks are even happening.

Overall, I think these speculative tests are not worth their maintenance burden.

Bug: 885401
Change-Id: I2574d690dc5596513bc089efd1738805ccd0404d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1863673Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Commit-Queue: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707248}

chrome/test/data/webui/polymer_browser_test_base.js

@@ -108,44 +108,6 @@ PolymerTest.prototype = {
       });
     }
   },
-
-  /** @override */
-  tearDown: function() {
-    // Note: We do this in tearDown() so that we have a chance to stamp all the
-    // dom-if templates, add elements through interaction, etc.
-    PolymerTest.testIronIcons(document.body);
-
-    testing.Test.prototype.tearDown.call(this);
-  }
-};
-
-/**
- * Tests that any iron-icon child of an HTML element has a corresponding
- * non-empty svg element.
- * @param {!HTMLElement} e The element to check the iron icons in.
- */
-PolymerTest.testIronIcons = function(e) {
-  e.querySelectorAll('* /deep/ iron-icon').forEach(function(icon) {
-    // Early return if the src is set instead of the icon, since the tests
-    // below will not work correctly in this case.
-    if (icon.src && !icon.icon) {
-      return;
-    }
-
-    // If the icon isn't set (or is set to ''), then don't test this. Having no
-    // set icon is valid for cases when we don't want to display anything.
-    if (!icon.icon) {
-      var rect = icon.getBoundingClientRect();
-      expectFalse(
-          rect.width * rect.height > 0,
-          'iron-icon with undefined "icon" is visible in the DOM.');
-      return;
-    }
-    var svg = icon.$$('svg');
-    expectTrue(
-        !!svg && svg.innerHTML != '',
-        'icon "' + icon.icon + '" is not present');
-  });
 };
 
 /**

chrome/test/data/webui/settings/site_details_permission_tests.js

@@ -34,11 +34,6 @@ suite('SiteDetailsPermission', function() {
     settings.SiteSettingsPrefsBrowserProxyImpl.instance_ = browserProxy;
     PolymerTest.clearBody();
     testElement = document.createElement('site-details-permission');
-
-    // Set the camera icon on <site-details-permission> manually to avoid
-    // failures on undefined icons during teardown in PolymerTest.testIronIcons.
-    // In practice, this is done from the parent.
-    testElement.icon = 'cr:videocam';
     document.body.appendChild(testElement);
   });