bluetooth: Small web-bluetooth-test.js cleanup

third_party/WebKit/LayoutTests/resources/bluetooth/web-bluetooth-test.js

 (() => {
   let mojo_;
 
   async function loadFakeBluetoothInterfaces() {
     if(typeof mojo_ !== 'undefined') {
       return mojo_;
     }
 
     if (typeof loadMojoModules === 'undefined') {
       throw 'Mojo is required for this API.'
     }
 
     mojo_ = await loadMojoModules('fakeBluetooth', [
       'mojo/public/js/bindings',
       'device/bluetooth/public/interfaces/test/fake_bluetooth.mojom'
     ]);
 
    [mojo_.bindings, mojo_.FakeBluetooth] = mojo_.modules;
     return mojo_;
   }
 
   class FakeBluetooth {
     constructor() {
       this.fake_bluetooth_ptr_ = undefined;
     }
 
     // Set it to indicate whether the platform supports BLE. For example,
     // Windows 7 is a platform that doesn't support Low Energy. On the other
     // hand Windows 10 is a platform that does support LE, even if there is no
-    // Bluetooth radio available.
-    async setLESupported(available) {
-      if (typeof available !== 'boolean') throw 'Type Not Supported';
-      await (await this.getFakeBluetoothInterface_()).setLESupported(available);
+    // Bluetooth radio present.
+    async setLESupported(supported) {
+      // Call setBluetoothFakeAdapter() to clean up any fake adapters left over
+      // by legacy tests.
+      // Legacy tests that use setBluetoothFakeAdapter() sometimes fail to clean
+      // their fake adapter. This is not a problem for these tests because the
+      // next setBluetoothFakeAdapter() will clean it up anyway but it is a
+      // problem for the new tests that do not use setBluetoothFakeAdapter().
+      // TODO(crbug.com/569709): Remove once setBluetoothFakeAdapter is no
+      // longer used.
+      await setBluetoothFakeAdapter('');
+
+      if (typeof supported !== 'boolean') throw 'Type Not Supported';
+      await (await this.getFakeBluetoothInterface_()).setLESupported(supported);
     }
 
     async getFakeBluetoothInterface_() {
       if (typeof this.fake_bluetooth_ptr_ !== 'undefined') {
         return this.fake_bluetooth_ptr_;
       }
 
       let mojo = await loadFakeBluetoothInterfaces();
 
       this.fake_bluetooth_ptr_ = new mojo.FakeBluetooth.FakeBluetoothPtr(
       mojo.interfaces.getInterface(
         mojo.FakeBluetooth.FakeBluetooth.name));
 
       return this.fake_bluetooth_ptr_;
     }
   }
 
   navigator.bluetooth.test = new FakeBluetooth();
 })();