Developer settings: Disable wifi scan throttling

Add a new developer settings toggle to allow users to
toggle wifi scan throttling off.

Bug: 112825565
Test: atest com.android.settings.development
Test: Manual verification of the new switch.
Change-Id: I1d8c149305ca92957c7d1b9f28497291ca8b2bf7

src/com/android/settings/development/DevelopmentSettingsDashboardFragment.java

@@ -432,6 +432,7 @@ public class DevelopmentSettingsDashboardFragment extends RestrictedDashboardFra
         controllers.add(new CameraLaserSensorPreferenceController(context));
         controllers.add(new WifiDisplayCertificationPreferenceController(context));
         controllers.add(new WifiVerboseLoggingPreferenceController(context));
+        controllers.add(new WifiScanThrottlingPreferenceController(context));
         controllers.add(new MobileDataAlwaysOnPreferenceController(context));
         controllers.add(new TetheringHardwareAccelPreferenceController(context));
         controllers.add(new BluetoothDeviceNoNamePreferenceController(context));

src/com/android/settings/development/WifiScanThrottlingPreferenceController.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * 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 com.android.settings.development;
+
+import android.content.Context;
+import android.provider.Settings;
+
+import androidx.annotation.VisibleForTesting;
+import androidx.preference.Preference;
+import androidx.preference.SwitchPreference;
+
+import com.android.settings.core.PreferenceControllerMixin;
+import com.android.settingslib.development.DeveloperOptionsPreferenceController;
+
+public class WifiScanThrottlingPreferenceController extends DeveloperOptionsPreferenceController
+        implements Preference.OnPreferenceChangeListener, PreferenceControllerMixin {
+    private static final String WIFI_SCAN_THROTTLING_KEY = "wifi_scan_throttling";
+    @VisibleForTesting
+    static final int SETTING_THROTTLING_ENABLE_VALUE_ON = 1;  // default is throttling enabled.
+    @VisibleForTesting
+    static final int SETTING_THROTTLING_ENABLE_VALUE_OFF = 0;
+
+    public WifiScanThrottlingPreferenceController(Context context) {
+        super(context);
+    }
+
+    @Override
+    public String getPreferenceKey() {
+        return WIFI_SCAN_THROTTLING_KEY;
+    }
+
+    @Override
+    public boolean onPreferenceChange(Preference preference, Object newValue) {
+        final boolean isEnabled = (Boolean) newValue;
+        Settings.Global.putInt(mContext.getContentResolver(),
+                Settings.Global.WIFI_SCAN_THROTTLE_ENABLED,
+                isEnabled
+                        ? SETTING_THROTTLING_ENABLE_VALUE_ON
+                        : SETTING_THROTTLING_ENABLE_VALUE_OFF);
+        return true;
+    }
+
+    @Override
+    public void updateState(Preference preference) {
+        final int scanThrottleEnabled = Settings.Global.getInt(
+                mContext.getContentResolver(), Settings.Global.WIFI_SCAN_THROTTLE_ENABLED,
+                SETTING_THROTTLING_ENABLE_VALUE_ON);
+        ((SwitchPreference) mPreference).setChecked(
+                scanThrottleEnabled == SETTING_THROTTLING_ENABLE_VALUE_ON);
+    }
+
+    @Override
+    protected void onDeveloperOptionsSwitchDisabled() {
+        super.onDeveloperOptionsSwitchDisabled();
+        Settings.Global.putInt(mContext.getContentResolver(),
+                Settings.Global.WIFI_SCAN_THROTTLE_ENABLED, SETTING_THROTTLING_ENABLE_VALUE_ON);
+        ((SwitchPreference) mPreference).setChecked(true);
+    }
+}