MD Settings: Fix minor vertical jumps in animations

chrome/browser/resources/settings/settings_page/main_page_behavior.js

Index: chrome/browser/resources/settings/settings_page/main_page_behavior.js
diff --git a/chrome/browser/resources/settings/settings_page/main_page_behavior.js b/chrome/browser/resources/settings/settings_page/main_page_behavior.js
index 1f8b2a87a9b6fd50fed541bd6d92b97cd4968f56..f0081d9ab69f1a478dff3be8632f11d0b9c586de 100644
--- a/chrome/browser/resources/settings/settings_page/main_page_behavior.js
+++ b/chrome/browser/resources/settings/settings_page/main_page_behavior.js
@@ -264,7 +264,6 @@ var MainPageBehaviorImpl = {
    */
   playCollapseSection_: function(section) {
     var card = section.$.card;
-    var cardStyle = getComputedStyle(card);
 
     this.style.margin = '';
     section.$.header.hidden = false;
@@ -293,6 +292,11 @@ var MainPageBehaviorImpl = {
     // but account for scroll.
     var targetTop = card.getBoundingClientRect().top - this.scroller.scrollTop;
 
+    // Account for the section header.
+    targetTop += section.$.header.offsetHeight +
+        parseInt(getComputedStyle(section.$.header).marginBottom) +

[dpapad, 2016/05/09 23:35:53]

Let's pass 10 as the 2nd parameter of parseInt(), as suggested by the
documentation at
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Obje...,
(see "Always specify this parameter" bold text).

[michaelpg, 2016/05/10 00:36:18]

Done.

+        parseInt(getComputedStyle(section.$.header).marginTop);

[dpapad, 2016/05/09 23:35:53]

Guessing that getComputedStyles() calls are simply reading cached values (it is
not entirely clear from documentation)? If not, let's call it only once instead.

[michaelpg, 2016/05/10 00:36:18]

Done (i thought so but i can't verify it)

+
     var keyframes = [{
       top: startingTop + 'px',
       minHeight: cardHeightStart + 'px',