[Bluetooth] Sort device list in settings page

To improve user experience, this sorts the Bluetooth device list in
settings page so that the connected devices are shown on top followed by
non-connected devices.

BUG=b:168257187

Change-Id: I60fcb820d6a6409460970273aefb1824c7354ebf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2419379
Commit-Queue: Sonny Sasaka <sonnysasaka@chromium.org>
Reviewed-by: Ryan Hansberry <hansberry@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810820}

chrome/browser/resources/settings/chromeos/bluetooth_page/bluetooth_subpage.js

@@ -530,6 +530,18 @@ Polymer({
     }
   },
 
+  /**
+   * Return the sorted devices based on the connected statuses, connected
+   * devices are first followed by non-connected devices.
+   *
+   * @param {!Array<!chrome.bluetooth.Device>} devices
+   * @return {!Array<!chrome.bluetooth.Device>}
+   * @private
+   */
+  sortDevices_(devices) {
+    return devices.sort((a, b) => a.connected ? -1 : (b.connected ? 1 : 0));
+  },
+
   /**
    * Requests bluetooth device list from Chrome. Update deviceList_ once the
    * results are returned from chrome.
@@ -541,7 +553,7 @@ Polymer({
       limit: MAX_NUMBER_DEVICE_SHOWN
     };
     this.bluetooth.getDevices(filter, devices => {
-      this.deviceList_ = devices;
+      this.deviceList_ = this.sortDevices_(devices);
 
       // Check if we have yet to focus a deep-linked element.
       if (!this.pendingSettingId_) {