[CrOS Bluetooth] Close all mojo connections when pairing dialog closes.

Update <bluetooth-pairing-ui> to close all Mojo connections when it
is removed from the DOM. Previously, it would not do so, so if it is
removed from the DOM and Bluetooth is disabled, then re-enabled, it will
automatically start discovery because it is still observing
CrosBluetoothConfig properties. In some cases, this behavior can cause
Bluetooth to automatically re-enable after being disabled.

Recording: https://drive.google.com/file/d/1sIuCT-NLAurxRd22asYq_qlobOCO_kOy/view?usp=sharing

(cherry picked from commit cbf51ee)

Fixed: b/231738454
Change-Id: I51183eacdb9b0294d3de79d92075fa5f23345835
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3669998
Reviewed-by: Chad Duffin <chadduffin@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Chad Duffin <chadduffin@chromium.org>
Auto-Submit: Gordon Seto <gordonseto@google.com>
Cr-Original-Commit-Position: refs/heads/main@{#1008266}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3689704
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/branch-heads/5060@{#531}
Cr-Branched-From: b83393d-refs/heads/main@{#1002911}

chrome/test/data/webui/cr_components/chromeos/bluetooth/bluetooth_pairing_ui_test.js

@@ -1055,4 +1055,25 @@ suite('CrComponentsBluetoothPairingUiTest', function() {
     // Error text should no longer be showing.
     assertEquals(getDeviceSelectionPage().failedPairingDeviceId, '');
   });
+
+  // Regression test for b/231738454.
+  test(
+      'Mojo connections are closed after dialog is removed from DOM',
+      async function() {
+        await init();
+        assertEquals(1, bluetoothConfig.getNumStartDiscoveryCalls());
+
+        // Remove the pairing dialog from the DOM.
+        bluetoothPairingUi.remove();
+
+        // Disable Bluetooth.
+        bluetoothConfig.setSystemState(BluetoothSystemState.kDisabled);
+        await flushTasks();
+
+        // Re-enable Bluetooth. If the Mojo connections are still alive, this
+        // will trigger discovery to start again.
+        bluetoothConfig.setSystemState(BluetoothSystemState.kEnabled);
+        await flushTasks();
+        assertEquals(1, bluetoothConfig.getNumStartDiscoveryCalls());
+      });
 });

chrome/test/data/webui/cr_components/chromeos/bluetooth/fake_bluetooth_config.js

@@ -103,6 +103,9 @@ export class FakeBluetoothConfig {
      * @private {?FakeDevicePairingHandler}
      */
     this.lastPairingHandler_ = null;
+
+    /** @private {number} */
+    this.numStartDiscoveryCalls_ = 0;
   }
 
   /**
@@ -144,6 +147,7 @@ export class FakeBluetoothConfig {
     this.lastDiscoveryDelegate_ = delegate;
     this.notifyDiscoveryStarted_();
     this.notifyDelegatesPropertiesUpdated_();
+    this.numStartDiscoveryCalls_++;
   }
 
   /**
@@ -497,4 +501,11 @@ export class FakeBluetoothConfig {
         d => d.deviceProperties.id === deviceId);
     return device ? device : null;
   }
+
+  /**
+   * @return {number}
+   */
+  getNumStartDiscoveryCalls() {
+    return this.numStartDiscoveryCalls_;
+  }
 }

ui/webui/resources/cr_components/chromeos/bluetooth/bluetooth_pairing_ui.js

@@ -242,8 +242,6 @@ export class SettingsBluetoothPairingUiElement extends PolymerElement {
 
   ready() {
     super.ready();
-    getBluetoothConfig().observeSystemProperties(
-        this.systemPropertiesObserverReceiver_.$.bindNewPipeAndPassRemote());
 
     // If there's a specific device to pair with, immediately go to the spinner
     // page.
@@ -252,12 +250,28 @@ export class SettingsBluetoothPairingUiElement extends PolymerElement {
     }
   }
 
+  connectedCallback() {
+    super.connectedCallback();
+
+    getBluetoothConfig().observeSystemProperties(
+        this.systemPropertiesObserverReceiver_.$.bindNewPipeAndPassRemote());
+  }
+
   disconnectedCallback() {
     super.disconnectedCallback();
 
+    if (this.systemPropertiesObserverReceiver_) {
+      this.systemPropertiesObserverReceiver_.$.close();
+    }
     if (this.bluetoothDiscoveryDelegateReceiver_) {
       this.bluetoothDiscoveryDelegateReceiver_.$.close();
     }
+    if (this.pairingDelegateReceiver_) {
+      this.pairingDelegateReceiver_.$.close();
+    }
+    if (this.keyEnteredReceiver_) {
+      this.keyEnteredReceiver_.close();
+    }
   }
 
   /** @override */