Files app: File list CSS nits

Change column header sorting icon to use 'no-overlap' CSS class to
remove margin around the icon, instead of overwriting via CSS.

Remove unnecessary background and fill colors from display:none sort
icon.

Change rounded icons to use border-radius: 50% instead of static pixels.

Bug: 992821
Change-Id: Ia304ed3a89bdc58b32ab610a1880878d9d18cb0b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2049984
Auto-Submit: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#740218}

ui/file_manager/file_manager/foreground/css/file_manager.css

@@ -2207,9 +2207,8 @@ body.files-ng #list-container .table-header-cell:first-child
 
 body.files-ng .table-header-label .sort-icon {
   --cr-icon-button-icon-size: 16px;
-  --cr-icon-button-margin-start: 0px;
   --cr-icon-button-size: 32px;
-  border-radius: 16px;
+  border-radius: 50%;
 }
 
 body.files-ng .table-label-container {
@@ -2224,8 +2223,6 @@ body.files-ng .table-header-label .sorted .sort-icon:hover {
 }
 
 body.files-ng .table-header-label .not-sorted .sort-icon {
-  background-color: transparent;
-  --cr-icon-button-fill-color: transparent;
   display: none;
 }
 
@@ -2250,7 +2247,7 @@ body.files-ng.check-select #list-container list li[selected] .detail-thumbnail
 }
 
 body.files-ng #list-container list li .detail-thumbnail > .thumbnail {
-  border-radius: 16px;
+  border-radius: 50%;
 }
 
 body.files-ng .table-row-cell > * {

ui/file_manager/file_manager/foreground/js/ui/file_table.js

@@ -281,7 +281,7 @@ function renderHeader_(table) {
     const iconName = sortOrder === 'desc' ? 'down' : 'up';
     icon.setAttribute('iron-icon', `files16:arrow_${iconName}_small`);
     icon.setAttribute('tabindex', '-1');
-    icon.classList.add('sort-icon');
+    icon.classList.add('sort-icon', 'no-overlap');
 
     container.classList.toggle('not-sorted', !isSorted);
     container.classList.toggle('sorted', isSorted);