MD Settings: make iron list offset so items render onscreen

chrome/browser/resources/settings/search_engines_page/search_engines_page.js

Index: chrome/browser/resources/settings/search_engines_page/search_engines_page.js
diff --git a/chrome/browser/resources/settings/search_engines_page/search_engines_page.js b/chrome/browser/resources/settings/search_engines_page/search_engines_page.js
index 7e8c40f3a51a101d52d9fc44852524db80235205..dfdd6c5900e9c475559cbae82f9461c2caa14397 100644
--- a/chrome/browser/resources/settings/search_engines_page/search_engines_page.js
+++ b/chrome/browser/resources/settings/search_engines_page/search_engines_page.js
@@ -59,6 +59,14 @@ Polymer({
         getSearchEnginesList().then(this.enginesChanged_.bind(this));
     this.addWebUIListener(
         'search-engines-changed', this.enginesChanged_.bind(this));
+
+    // Sets offset in iron-list that uses the page as a scrollTarget.
+    // The scrollTarget doesn't know about headers and items above the list.
+    Polymer.RenderStatus.afterNextRender(this, function() {
+      // Size of headers is constant, but defaultEngines size can vary.
+      this.$.otherEngines.scrollOffset = 184 +

[Dan Beam, 2017/04/07 23:32:53]

this looks brittle, where does the 184 come from?  are you sure it's the same on
all platforms?  what happens if this changes?

[hcarmona, 2017/04/08 00:02:01]

Agreed, for parts that are in this file, I can add an ID and get the height
using the client rect...
Maybe putting them in a div and getting the height of that?
But, the header on the top of the page is outside the shadow dom.

Suggestions?

[Dan Beam, 2017/04/08 00:09:44]

offsetTop

[hcarmona, 2017/04/08 00:24:40]

Sweet. Done.

+          this.$.defaultEngines.getBoundingClientRect().height;
+    });
   },
 
   /** @private */