Fix broken robotests.

In ag/2580164 AccessPoint.java made a reference to WifiTracker, which
in term references WifiNetworkScoreCache. Since the Robolectric in the
platform still has not been updated to support API 26 (Android O), this
caused the test to break.

By definining the class in the test package, the test can be fixed until
proper Android O support is added to the robolectric prebuilts in the
platform code.

Bug: 64217019
Test: make -j40 RunSettingsLibRoboTests
Change-Id: I6cfd5c17d1aba98d43cca4828058493960a7ff79

packages/SettingsLib/tests/robotests/src/android/net/wifi/WifiNetworkScoreCache.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2017 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.wifi;
+
+import android.content.Context;
+import android.os.Handler;
+
+import java.util.List;
+
+/**
+ * Will be removed once robolectric is updated to O
+ */
+public class WifiNetworkScoreCache {
+
+    public WifiNetworkScoreCache(Context context, WifiNetworkScoreCache.CacheListener listener) {
+    }
+
+    public abstract static class CacheListener {
+        public CacheListener(Handler handler) {
+        }
+
+        void post(List updatedNetworks) {
+        }
+
+        public abstract void networkCacheUpdated(List updatedNetworks);
+    }
+}