Disable draw overlay for most of Settings.

Fixes: 120484087
Test: robotests
Change-Id: I1f7c8e83bd5054525bde5ca35fac55b7c9586c7c

src/com/android/settings/core/HideNonSystemOverlayMixin.java

@@ -0,0 +1,64 @@
+/*
+ * 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.core;
+
+import static android.view.WindowManager.LayoutParams.SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS;
+
+import static androidx.lifecycle.Lifecycle.Event.ON_START;
+import static androidx.lifecycle.Lifecycle.Event.ON_STOP;
+
+import android.app.Activity;
+import android.view.Window;
+import android.view.WindowManager;
+
+import androidx.lifecycle.LifecycleObserver;
+import androidx.lifecycle.OnLifecycleEvent;
+
+
+/**
+ * A mixin that adds window flag to prevent non-system overlays showing on top of Settings
+ * activities.
+ */
+public class HideNonSystemOverlayMixin implements LifecycleObserver {
+
+    private final Activity mActivity;
+
+    public HideNonSystemOverlayMixin(Activity activity) {
+        mActivity = activity;
+    }
+
+    @OnLifecycleEvent(ON_START)
+    public void onStart() {
+        if (mActivity == null) {
+            return;
+        }
+        mActivity.getWindow().addSystemFlags(SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS);
+        android.util.EventLog.writeEvent(0x534e4554, "120484087", -1, "");
+    }
+
+
+    @OnLifecycleEvent(ON_STOP)
+    public void onStop() {
+        if (mActivity == null) {
+            return;
+        }
+        final Window window = mActivity.getWindow();
+        final WindowManager.LayoutParams attrs = window.getAttributes();
+        attrs.privateFlags &= ~SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS;
+        window.setAttributes(attrs);
+    }
+}

src/com/android/settings/core/SettingsBaseActivity.java

@@ -32,7 +32,6 @@ import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.Window;
-import android.view.WindowManager.LayoutParams;
 import android.widget.Toolbar;
 
 import androidx.fragment.app.FragmentActivity;
@@ -59,8 +58,8 @@ public class SettingsBaseActivity extends FragmentActivity {
     @Override
     protected void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-
         final long startTime = System.currentTimeMillis();
+        getLifecycle().addObserver(new HideNonSystemOverlayMixin(this));
 
         final TypedArray theme = getTheme().obtainStyledAttributes(android.R.styleable.Theme);
         if (!theme.getBoolean(android.R.styleable.Theme_windowNoTitle, false)) {