Add icon-visibility attribute to cr.ui.Tree.

chrome/browser/resources/shared/css/tree.css

 tree {
   outline: none;
   overflow: auto;
   display: block;
 }
 
 .tree-item > .tree-row {
   color: black;
   -webkit-user-select: none;
   border: 1px solid rgba(255,255,255,0); /* transparent white */
@@ skipping 81 matching lines @@
 .tree-children {
   display: none;
 }
 
 .tree-item > .tree-row > * {
   display: inline-block;
   box-sizing: border-box;
 }
 
 .tree-label {
-  -webkit-padding-start: 20px;
-  background-image: url("../../../../../ui/resources/folder_closed.png");
-  background-position: 0 50%;
-  background-repeat: no-repeat;
   white-space: pre;
 }
 
+tree[icon-visibility] .tree-label {

[arv (Not doing code reviews), 2011/10/28 16:15:12]

Sorry, I should have paid more attention the first round.

<tree> should work like before. The default behavior should not require an
attribute.

So what are the options here?

a) <tree>
b) <tree icon-visibility="">
c) <tree icon-visibility="all">
d) <tree icon-visibility="parent">

A and c seems to be the same to me then. What does b do?

[flackr, 2011/10/28 22:32:50]

If A and C are the same then this needs to change. Before, A did not reserve
space for icons, where B does. The way it is now (not having set a default
property value), A and B will be the same as D, not C.

On 2011/10/28 16:15:12, arv wrote:

[arv (Not doing code reviews), 2011/10/28 22:41:03]

To me, the important part is that <tree> does not change. I also find <tree
icon-visibility=""> strange.

[flackr, 2011/10/31 14:37:56]

Okay, the default behaviour will be as it was before, the equivalent of 'all'.
There's no reason to use icon-visibility="" as it's no different than not
specifying it now.

+  -webkit-padding-start: 20px;
+  background-position: 0 50%;
+  background-repeat: no-repeat;
+}
+
+tree[icon-visibility=all] .tree-label,
+tree[icon-visibility=parent] .tree-row[may-have-children] > .tree-label {
+  background-image: url("../../../../../ui/resources/folder_closed.png");
+}
+
+tree[icon-visibility=parent] .tree-row[has-children=false] > .tree-label {
+  background-image: none;
+}
+
+tree[icon-visibility] .tree-item[expanded] > .tree-row > .tree-label {
+  background-image: url("../../../../../ui/resources/folder_open.png");
+}
+
 /* We need to ensure that even empty labels take up space */
 .tree-label:empty:after {
   content: " ";
   white-space: pre;
 }
 
 .tree-rename > .tree-row > .tree-label {
   -webkit-user-select: auto;
   -webkit-user-modify: read-write-plaintext-only;
   background: white;
   color: black;
   outline: 1px solid black;
 }
 
 html[dir=rtl] .tree-label {
   background-position: 100% 50%;
 }
 
-.tree-item[expanded] > .tree-row > .tree-label {
-  background-image: url("../../../../../ui/resources/folder_open.png");
-}
-
-html[dir='rtl'] .tree-label {
+html[dir=rtl] tree[icon-visibility=all] .tree-label,
+html[dir=rtl] tree[icon-visibility=parent] .tree-row[may-have-children]
+    > .tree-label {
   background-image: url("../../../../../ui/resources/folder_closed_rtl.png");
 }
 
-html[dir='rtl'] .tree-item[expanded] > .tree-row > .tree-label {
+html[dir=rtl] tree[icon-visibility] .tree-item[expanded] > .tree-row
+    > .tree-label {
   background-image: url("../../../../../ui/resources/folder_open_rtl.png");
 }
 
 .tree-item[editing] input {
   /* Do not inherit the line-height */
   font-family: inherit;
   font-size: inherit;
   font-weight: inherit;
   margin: -2px -8px -2px -3px;
   padding: 1px 7px 1px 1px;
 }
 
 html:not([os=mac]) .tree-item[editing] input {
   outline: none;
 }
 
 html[dir=rtl] .tree-item[editing] input {
   margin: -2px -3px -2px -8px;
   padding: 1px 1px 1px 7px;
 }