[DevTools] Simplify Popover API

third_party/WebKit/Source/devtools/front_end/elements/ElementsTreeOutline.js

Index: third_party/WebKit/Source/devtools/front_end/elements/ElementsTreeOutline.js
diff --git a/third_party/WebKit/Source/devtools/front_end/elements/ElementsTreeOutline.js b/third_party/WebKit/Source/devtools/front_end/elements/ElementsTreeOutline.js
index e60a30a40de62f08954f133263acd190aa6ac162..d48b56d0bfe9e2b7a5aafd7ee2f972434526716c 100644
--- a/third_party/WebKit/Source/devtools/front_end/elements/ElementsTreeOutline.js
+++ b/third_party/WebKit/Source/devtools/front_end/elements/ElementsTreeOutline.js
@@ -77,6 +77,7 @@ Elements.ElementsTreeOutline = class extends UI.TreeOutline {
 
     this._popoverHelper = new UI.PopoverHelper(this._element);
     this._popoverHelper.initializeCallbacks(this._getPopoverAnchor.bind(this), this._showPopover.bind(this));
+    this._popoverHelper.setHasPadding(true);
     this._popoverHelper.setTimeout(0, 100);
 
     /** @type {!Map<!SDK.DOMNode, !Elements.ElementsTreeOutline.UpdateRecord>} */
@@ -572,23 +573,27 @@ Elements.ElementsTreeOutline = class extends UI.TreeOutline {
 
   /**
    * @param {!Element} link
-   * @param {!UI.Popover} popover
+   * @param {!UI.GlassPane} popover
+   * @return {!Promise<boolean>}
    */
   _showPopover(link, popover) {
+    var fulfill;
+    var promise = new Promise(x => fulfill = x);
     var listItem = link.enclosingNodeOrSelfWithNodeName('li');
     var node = /** @type {!Elements.ElementsTreeElement} */ (listItem.treeElement).node();
     this._loadDimensionsForNode(
         node, Components.DOMPresentationUtils.buildImagePreviewContents.bind(
                   Components.DOMPresentationUtils, node.target(), link[Elements.ElementsTreeElement.HrefSymbol], true,
                   showPopover));
+    return promise;
 
     /**
      * @param {!Element=} contents
      */
     function showPopover(contents) {
-      if (!contents)
-        return;
-      popover.showForAnchor(contents, link);
+      if (contents)
+        popover.contentElement.appendChild(contents);
+      fulfill(!!contents);
     }
   }