Introduce HardwareOverlaysPreferenceController

- Create new HardwareOverlaysPreferenceController
 - Create controller inside the DashboardFragment
 - Port logic from DevelopmentSettings into the controller
 - Added ShadowParcel to help with testing
 HardwareOverlaysPreferenceController and
 ShowSurfaceUpdatesPreferenceController

Bug: 34203528
Test: make RunSettingsRoboTests -j40
Change-Id: Ib6b9679f2a2d2ec84f91da5ac0b68cb2b21eea72

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

@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 2017 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.os.IBinder;
+import android.os.Parcel;
+import android.os.RemoteException;
+import android.os.ServiceManager;
+import android.support.annotation.VisibleForTesting;
+import android.support.v14.preference.SwitchPreference;
+import android.support.v7.preference.Preference;
+import android.support.v7.preference.PreferenceScreen;
+
+public class HardwareOverlaysPreferenceController extends DeveloperOptionsPreferenceController
+        implements Preference.OnPreferenceChangeListener {
+
+    private static final String DISABLE_OVERLAYS_KEY = "disable_overlays";
+
+    private static final int SETTING_VALUE_ON = 1;
+    private static final int SETTING_VALUE_OFF = 0;
+    private static final String SURFACE_FLINGER_SERVICE_KEY = "SurfaceFlinger";
+
+    @VisibleForTesting
+    static final int SURFACE_FLINGER_READ_CODE = 1010;
+
+    private static final int SURFACE_FLINGER_DISABLE_OVERLAYS_CODE = 1008;
+    private static final String SURFACE_COMPOSER_INTERFACE_KEY = "android.ui.ISurfaceComposer";
+
+    private final IBinder mSurfaceFlinger;
+    private SwitchPreference mPreference;
+
+    public HardwareOverlaysPreferenceController(Context context) {
+        super(context);
+        mSurfaceFlinger = ServiceManager.getService(SURFACE_FLINGER_SERVICE_KEY);
+    }
+
+    @Override
+    public String getPreferenceKey() {
+        return DISABLE_OVERLAYS_KEY;
+    }
+
+    @Override
+    public void displayPreference(PreferenceScreen screen) {
+        super.displayPreference(screen);
+
+        mPreference = (SwitchPreference) screen.findPreference(getPreferenceKey());
+    }
+
+    @Override
+    public boolean onPreferenceChange(Preference preference, Object newValue) {
+        final boolean isEnabled = (Boolean) newValue;
+        writeHardwareOverlaysSetting(isEnabled);
+        return true;
+    }
+
+    @Override
+    public void updateState(Preference preference) {
+        updateHardwareOverlaysSetting();
+    }
+
+    @Override
+    protected void onDeveloperOptionsSwitchEnabled() {
+        mPreference.setEnabled(true);
+    }
+
+    @Override
+    protected void onDeveloperOptionsSwitchDisabled() {
+        if (mPreference.isChecked()) {
+            // Writing false to the preference when the setting is already off will have a
+            // side effect of turning on the preference that we wish to avoid
+            writeHardwareOverlaysSetting(false);
+            mPreference.setChecked(false);
+        }
+        mPreference.setEnabled(false);
+    }
+
+    @VisibleForTesting
+    void updateHardwareOverlaysSetting() {
+        if (mSurfaceFlinger == null) {
+            return;
+        }
+        // magic communication with surface flinger.
+        try {
+            final Parcel data = Parcel.obtain();
+            final Parcel reply = Parcel.obtain();
+            data.writeInterfaceToken(SURFACE_COMPOSER_INTERFACE_KEY);
+            mSurfaceFlinger.transact(SURFACE_FLINGER_READ_CODE, data, reply, 0 /* flags */);
+            @SuppressWarnings("unused") final int showCpu = reply.readInt();
+            @SuppressWarnings("unused") final int enableGL = reply.readInt();
+            @SuppressWarnings("unused") final int showUpdates = reply.readInt();
+            @SuppressWarnings("unused") final int showBackground = reply.readInt();
+            final int disableOverlays = reply.readInt();
+            mPreference.setChecked(disableOverlays != SETTING_VALUE_OFF);
+            reply.recycle();
+            data.recycle();
+        } catch (RemoteException ex) {
+            // intentional no-op
+        }
+    }
+
+    @VisibleForTesting
+    void writeHardwareOverlaysSetting(boolean isEnabled) {
+        if (mSurfaceFlinger == null) {
+            return;
+        }
+        try {
+            final Parcel data = Parcel.obtain();
+            data.writeInterfaceToken(SURFACE_COMPOSER_INTERFACE_KEY);
+            final int disableOverlays = isEnabled ? SETTING_VALUE_ON : SETTING_VALUE_OFF;
+            data.writeInt(disableOverlays);
+            mSurfaceFlinger.transact(SURFACE_FLINGER_DISABLE_OVERLAYS_CODE, data,
+                    null /* reply */, 0 /* flags */);
+            data.recycle();
+        } catch (RemoteException ex) {
+            // intentional no-op
+        }
+        updateHardwareOverlaysSetting();
+    }
+}