bluetooth: Small web-bluetooth-test.js cleanup

Two changes:
 1. Call setBluetoothFakeAdapter('') to clean up any adapters left
    by legacy tests.
 2. Change 'available' to 'supported' to match the functions name.

BUG=569709

Review-Url: https://codereview.chromium.org/2859673003
Cr-Commit-Position: refs/heads/master@{#469002}

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

@@ -27,10 +27,20 @@
     // 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_() {