Bug 1419172 - Stop the attachment icon's flickering when selecting/deselecting. r=aceman

mail/themes/linux/mail/attachmentList.css

@@ -5,7 +5,9 @@
 /* styles for the attachment list */
 
 .attachmentcell-icon {
-  padding: 1px;
+  margin: 1px;
+  width: 16px;
+  height: 16px;
 }
 
 .attachmentcell-name,
@@ -45,6 +47,10 @@ attachmentlist:focus > attachmentitem[selected="true"] .attachmentcell-nameselec
   color: HighlightText;
 }
 
+attachmentitem[selected="true"] .attachmentcell-icon {
+  filter: url("chrome://messenger/skin/imageFilters.svg#selected");
+}
+
 attachmentlist:focus > attachmentitem[selected="true"] .attachmentcell-icon {
   filter: url("chrome://messenger/skin/imageFilters.svg#selected-focus");
 }

mail/themes/linux/mail/imageFilters.svg

@@ -4,6 +4,14 @@
    - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
 
 <svg xmlns="http://www.w3.org/2000/svg">
+  <filter id="selected">
+    <feFlood flood-color="-moz-CellHighlight" flood-opacity="0.5" result="color"/>
+    <feComposite in="color" in2="SourceAlpha" operator="in" result="mask"/>
+    <feMerge>
+      <feMergeNode in="SourceGraphic"/>
+      <feMergeNode in="mask"/>
+    </feMerge>
+  </filter>
   <filter id="selected-focus">
     <feFlood flood-color="Highlight" flood-opacity="0.7" result="color"/>
     <feComposite in="color" in2="SourceAlpha" operator="in" result="mask"/>

mail/themes/osx/mail/attachmentList.css

@@ -7,7 +7,7 @@
 /* ::::: attachment list ::::: */
 
 .attachmentcell-icon {
-  padding: 1px;
+  margin: 1px;
   width: 16px;
   height: 16px;
 }

mail/themes/windows/mail/attachmentList.css

@@ -5,7 +5,9 @@
 /* styles for the attachment list */
 
 .attachmentcell-icon {
-  padding: 1px;
+  margin: 1px;
+  width: 16px;
+  height: 16px;
 }
 
 .attachmentcell-name,