Iron List: Remove usage of /deep/

/deep/ selector no longer works in Polymer 2. Update iron-list to find
the focused element differently.

Bug: 899113
Change-Id: I5c548adbe680a5980638e4905bffdf7fceb977e6
Reviewed-on: https://chromium-review.googlesource.com/c/1316443Reviewed-by: Scott Chen <scottchen@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606715}

third_party/polymer/v1_0/chromium.patch

@@ -27,8 +27,44 @@ index 43c59653a39b..26652936735c 100644
 +        value: false
        }
      },
+@@ -786,6 +794,39 @@
+       newGrid && this._updateGridMetrics();
+     },
 
-@@ -791,6 +799,15 @@
++    /**
++     * Finds and returns the focused element (both within self and children's
++     * Shadow DOM).
++     * @return {?HTMLElement}
++     */
++    _getFocusedElement: function() {
++      function doSearch(node, query) {
++        let result = null;
++        let type = node.nodeType;
++        if (type == Node.ELEMENT_NODE || type == Node.DOCUMENT_FRAGMENT_NODE)
++          result = node.querySelector(query);
++        if (result)
++          return result;
++
++        let child = node.firstChild;
++        while (child !== null && result === null) {
++          result = doSearch(child, query);
++          child = child.nextSibling;
++        }
++        if (result)
++          return result;
++
++        const shadowRoot = node.shadowRoot;
++        return shadowRoot ? doSearch(shadowRoot, query) : null;
++      }
++
++      // Find out if any of the items are focused first, and only search
++      // recursively in the item that contains focus, to avoid a slow
++      // search of the entire list.
++      const focusWithin = doSearch(this, ':focus-within');
++      return focusWithin ? doSearch(focusWithin, ':focus') : null;
++    },
++
+@@ -791,6 +836,15 @@
       * to `items`, splices or updates to a single item.
       */
      _itemsChanged: function(change) {
@@ -44,7 +80,7 @@ index 43c59653a39b..26652936735c 100644
        if (change.path === 'items') {
          this._virtualStart = 0;
          this._physicalTop = 0;
-@@ -804,7 +821,7 @@
+@@ -804,7 +858,7 @@
          this._physicalItems = this._physicalItems || [];
          this._physicalSizes = this._physicalSizes || [];
          this._physicalStart = 0;
@@ -53,7 +89,7 @@ index 43c59653a39b..26652936735c 100644
            this._resetScrollPosition(0);
          }
          this._removeFocusedItem();
-@@ -826,6 +843,17 @@
+@@ -826,6 +880,17 @@
        } else if (change.path !== 'items.length') {
          this._forwardItemPath(change.path, change.value);
        }

third_party/polymer/v1_0/components-chromium/iron-list/iron-list-extracted.js

@@ -794,6 +794,39 @@
       newGrid && this._updateGridMetrics();
     },
 
+    /**
+     * Finds and returns the focused element (both within self and children's
+     * Shadow DOM).
+     * @return {?HTMLElement}
+     */
+    _getFocusedElement: function() {
+      function doSearch(node, query) {
+        let result = null;
+        let type = node.nodeType;
+        if (type == Node.ELEMENT_NODE || type == Node.DOCUMENT_FRAGMENT_NODE)
+          result = node.querySelector(query);
+        if (result)
+          return result;
+
+        let child = node.firstChild;
+        while (child !== null && result === null) {
+          result = doSearch(child, query);
+          child = child.nextSibling;
+        }
+        if (result)
+          return result;
+
+        const shadowRoot = node.shadowRoot;
+        return shadowRoot ? doSearch(shadowRoot, query) : null;
+      }
+
+      // Find out if any of the items are focused first, and only search
+      // recursively in the item that contains focus, to avoid a slow
+      // search of the entire list.
+      const focusWithin = doSearch(this, ':focus-within');
+      return focusWithin ? doSearch(focusWithin, ':focus') : null;
+    },
+
     /**
      * Called when the items have changed. That is, reassignments
      * to `items`, splices or updates to a single item.
@@ -803,7 +836,7 @@
       var lastFocusedIndex, focusedElement;
       if (rendering && this.preserveFocus) {
         lastFocusedIndex = this._focusedVirtualIndex;
-        focusedElement = this.querySelector('* /deep/ *:focus');
+        focusedElement = this._getFocusedElement();
       }
 
       var preservingFocus = rendering && this.preserveFocus && focusedElement;