bluetooth: Add characteristics to the device's attribute instance map

third_party/WebKit/LayoutTests/bluetooth/script-tests/characteristic-get-same-object.js

+'use strict';
+promise_test(() => {
+  return setBluetoothFakeAdapter('HeartRateAdapter')
+    .then(() => requestDeviceWithKeyDown({
+      filters: [{services: ['heart_rate']}]}))
+    .then(device => device.gatt.connect())
+    .then(gattServer => gattServer.getPrimaryService('heart_rate'))
+    .then(service => Promise.all([
+      service.CALLS([
+        getCharacteristic('body_sensor_location')|
+        getCharacteristics()|
+        getCharacteristics('body_sensor_location')[UUID]]),
+      service.PREVIOUS_CALL]))
+    .then(characteristics_arrays => {
+      // Convert to arrays if necessary.
+      for (let i = 0; i < characteristics_arrays.length; i++) {
+        characteristics_arrays[i] = [].concat(characteristics_arrays[i]);
+      }
+
+      for (let i = 1; i < characteristics_arrays.length; i++) {
+        assert_equals(characteristics_arrays[0].length,
+                      characteristics_arrays[i].length);
+      }
+
+      let base_set = new Set(characteristics_arrays[0]);
+      for (let characteristics of characteristics_arrays) {
+        characteristics.forEach(
+          characteristic => assert_true(base_set.has(characteristic)));
+      }
+    });
+}, 'Calls to FUNCTION_NAME should return the same object.');