[MD Bookmarks] Make folder nodes extend their whole width.

chrome/browser/resources/md_bookmarks/folder_node.js

Index: chrome/browser/resources/md_bookmarks/folder_node.js
diff --git a/chrome/browser/resources/md_bookmarks/folder_node.js b/chrome/browser/resources/md_bookmarks/folder_node.js
index cb1ea0b46cfd9703b60f3ca75eb92236ad649fce..a52b3c9dbf683ebccfeaa2a016b5b21d04b72252 100644
--- a/chrome/browser/resources/md_bookmarks/folder_node.js
+++ b/chrome/browser/resources/md_bookmarks/folder_node.js
@@ -15,6 +15,11 @@ Polymer({
       observer: 'updateFromStore',
     },
 
+    depth: {
+      type: Number,
+      observer: 'depthChanged_',
+    },
+
     /** @type {BookmarkNode} */
     item: Object,
 
@@ -74,6 +79,12 @@ Polymer({
         bookmarks.actions.changeFolderOpen(this.item.id, this.isClosed));
   },
 
+  /**
+   * @private
+   * @param {string} itemId
+   * @param {string} selectedFolder
+   * @return {boolean}
+   */
   computeIsSelected_: function(itemId, selectedFolder) {
     return itemId == selectedFolder;
   },
@@ -91,6 +102,20 @@ Polymer({
     return false;
   },
 
+  /** @private */
+  depthChanged_: function() {
+    this.$['folder-label'].style.paddingLeft =

[tsergeant, 2017/03/07 23:32:50]

I wonder if there's any way we can do this with custom property magic. Like,

this.$['--node-depth'] = '3'

and then in css:

padding-left: calc(var(--node-depth) * var(--padding-left-per-depth))

Unfortunately, assigning custom properties into this.style doesn't seem to work.

[calamity, 2017/03/08 06:52:45]

Magic installed.

+        `calc(${this.depth} * var(--padding-left-per-depth))`;
+  },
+
+  /**
+   * @private
+   * @return {number}
+   */
+  getChildDepth_: function() {
+    return this.depth + 1;
+  },
+
   /**
    * @param {string} itemId
    * @private