[list.js] Consider vertical paddings of list view when scrolling

ui/webui/resources/js/cr/ui/list.js

Index: ui/webui/resources/js/cr/ui/list.js
diff --git a/ui/webui/resources/js/cr/ui/list.js b/ui/webui/resources/js/cr/ui/list.js
index 6377273124467465801854953c4d9fc396b1c2a2..27e1d678cb02a46dbd58fc330947245bd96ecf51 100644
--- a/ui/webui/resources/js/cr/ui/list.js
+++ b/ui/webui/resources/js/cr/ui/list.js
@@ -711,6 +711,11 @@ cr.define('cr.ui', function() {
       var top = this.getItemTop(index);
       var clientHeight = this.clientHeight;
 
+      var cs = getComputedStyle(this);
+      var paddingY = parseInt(cs.paddingTop, 10) +
+                     parseInt(cs.paddingBottom, 10);
+      var availableHeight = clientHeight - paddingY;
+
       var self = this;
       // Function to adjust the tops of viewport and row.
       function scrollToAdjustTop() {
@@ -719,27 +724,20 @@ cr.define('cr.ui', function() {
       };
       // Function to adjust the bottoms of viewport and row.
       function scrollToAdjustBottom() {
-          var cs = getComputedStyle(self);
-          var paddingY = parseInt(cs.paddingTop, 10) +
-                         parseInt(cs.paddingBottom, 10);
-
-          if (top + itemHeight > scrollTop + clientHeight - paddingY) {
-            self.scrollTop = top + itemHeight - clientHeight + paddingY;
-            return true;
-          }
-          return false;
+          self.scrollTop = top + itemHeight - availableHeight;

[arv (Not doing code reviews), 2013/12/02 16:30:27]

This changes the behavior too.

In the old code we only scrolled if the item was outside the viewport. Now we
scroll to the bottom at all times.

...but it seems like this case is already covered.

[yoshiki, 2013/12/03 01:12:02]

Yes, this check is already done in the callers.

+          return true;
       };
 
       // Check if the entire of given indexed row can be shown in the viewport.
-      if (itemHeight <= clientHeight) {
+      if (itemHeight <= availableHeight) {
         if (top < scrollTop)
           return scrollToAdjustTop();
-        if (scrollTop + clientHeight < top + itemHeight)
+        if (scrollTop + availableHeight < top + itemHeight)
           return scrollToAdjustBottom();
       } else {
         if (scrollTop < top)
           return scrollToAdjustTop();
-        if (top + itemHeight < scrollTop + clientHeight)
+        if (top + itemHeight < scrollTop + availableHeight)
           return scrollToAdjustBottom();
       }
       return false;