Compile print_preview, part 5: reduce down to 104 errors

chrome/browser/resources/print_preview/print_preview_animations.js

Index: chrome/browser/resources/print_preview/print_preview_animations.js
diff --git a/chrome/browser/resources/print_preview/print_preview_animations.js b/chrome/browser/resources/print_preview/print_preview_animations.js
index b864d552aa3d40fd2b9fca007d549cbfaa31cfa7..56f293019a990aeabaaf7be96ad809c974ba6ac8 100644
--- a/chrome/browser/resources/print_preview/print_preview_animations.js
+++ b/chrome/browser/resources/print_preview/print_preview_animations.js
@@ -73,7 +73,11 @@ function fadeOutElement(el) {
   el.style.height = 'auto';
   var height = el.offsetHeight;
   el.style.height = height + 'px';
-  el.offsetHeight;  // Should force an update of the computed style.
+  /**
+   * Should force an update of the computed style.
+   * @suppress {uselessCode}
+   */
+  el.offsetHeight;
   animationEventTracker_.add(
       el, 'webkitTransitionEnd', onFadeOutTransitionEnd.bind(el), false);
   el.classList.add('closing');
@@ -129,9 +133,11 @@ function fadeInOption(el, opt_justShow) {
   // To make the option visible during the first fade in.
   el.hidden = false;
 
-  var leftColumn = el.querySelector('.left-column');
+  var leftColumn = assertInstanceof(el.querySelector('.left-column'),
+                                    HTMLElement);
   wrapContentsInDiv(leftColumn, ['invisible']);
-  var rightColumn = el.querySelector('.right-column');
+  var rightColumn = assertInstanceof(el.querySelector('.right-column'),
+                                     HTMLElement);
   wrapContentsInDiv(rightColumn, ['invisible']);
 
   var toAnimate = el.querySelectorAll('.collapsible');
@@ -150,9 +156,11 @@ function fadeOutOption(el, opt_justHide) {
   if (!el.classList.contains('visible'))
     return;
 
-  var leftColumn = el.querySelector('.left-column');
+  var leftColumn = assertInstanceof(el.querySelector('.left-column'),
+                                    HTMLElement);
   wrapContentsInDiv(leftColumn, ['visible']);
-  var rightColumn = el.querySelector('.right-column');
+  var rightColumn = assertInstanceof(el.querySelector('.right-column'),
+                                     HTMLElement);
   wrapContentsInDiv(rightColumn, ['visible']);
 
   var toAnimate = el.querySelectorAll('.collapsible');
@@ -173,7 +181,7 @@ function fadeOutOption(el, opt_justHide) {
  * |classes| in the new div, only if has not been already done. It is necessary
  * for animating the height of table cells.
  * @param {HTMLElement} el The element to be processed.
- * @param {array} classes The css classes to add.
+ * @param {Array} classes The css classes to add.
  */
 function wrapContentsInDiv(el, classes) {
   var div = el.querySelector('div');