DO NOT MERGE Backporting potential usb tapjacking precaution.

Bug: 62187985
Test: manual, backport
Change-Id: I02f615624b33c3fb6e2fbb15ce44a0032b6f4387
(cherry picked from commit cc4bec01404ac375fc109448614143293688ce48)
diff --git a/packages/SystemUI/res/values/strings.xml b/packages/SystemUI/res/values/strings.xml
index f7a169c..b061c57 100644
--- a/packages/SystemUI/res/values/strings.xml
+++ b/packages/SystemUI/res/values/strings.xml
@@ -1702,4 +1702,9 @@
     <!-- accessibility label for paging indicator in quick settings [CHAR LIMITi=NONE] -->
     <string name="accessibility_quick_settings_page">Page <xliff:g name="current_page" example="1">%1$d</xliff:g> of <xliff:g name="num_pages" example="2">%2$d</xliff:g></string>
 
+    <!-- Warning shown when user input has been blocked due to another app overlaying screen
+     content. Since we don't know what the app is showing on top of the input target, we
+     can't verify user consent. [CHAR LIMIT=NONE] -->
+    <string name="touch_filtered_warning">Because an app is obscuring a permission request, Settings
+        can’t verify your response.</string>
 </resources>
diff --git a/packages/SystemUI/src/com/android/systemui/usb/UsbDebuggingActivity.java b/packages/SystemUI/src/com/android/systemui/usb/UsbDebuggingActivity.java
index f5447a2..0ba8c08 100644
--- a/packages/SystemUI/src/com/android/systemui/usb/UsbDebuggingActivity.java
+++ b/packages/SystemUI/src/com/android/systemui/usb/UsbDebuggingActivity.java
@@ -31,8 +31,12 @@
 import android.os.SystemProperties;
 import android.util.Log;
 import android.view.LayoutInflater;
+import android.view.MotionEvent;
 import android.view.View;
+import android.view.Window;
+import android.view.WindowManager;
 import android.widget.CheckBox;
+import android.widget.Toast;
 
 import com.android.internal.app.AlertActivity;
 import com.android.internal.app.AlertController;
@@ -48,6 +52,10 @@
 
     @Override
     public void onCreate(Bundle icicle) {
+        Window window = getWindow();
+        window.addPrivateFlags(WindowManager.LayoutParams.PRIVATE_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS);
+        window.setType(WindowManager.LayoutParams.TYPE_SYSTEM_DIALOG);
+
         super.onCreate(icicle);
 
         if (SystemProperties.getInt("service.adb.tcp.port", 0) == 0) {
@@ -79,6 +87,26 @@
         ap.mView = checkbox;
 
         setupAlert();
+
+        // adding touch listener on affirmative button - checks if window is obscured
+        // if obscured, do not let user give permissions (could be tapjacking involved)
+        final View.OnTouchListener filterTouchListener = new View.OnTouchListener() {
+
+            public boolean onTouch(View v, MotionEvent event) {
+                // Filter obscured touches by consuming them.
+                if (((event.getFlags() & MotionEvent.FLAG_WINDOW_IS_OBSCURED) != 0)
+                    || ((event.getFlags() & MotionEvent.FLAG_WINDOW_IS_PARTIALLY_OBSCURED) != 0)) {
+                    if (event.getAction() == MotionEvent.ACTION_UP) {
+                        Toast.makeText(v.getContext(),
+                                R.string.touch_filtered_warning,
+                                Toast.LENGTH_SHORT).show();
+                    }
+                    return true;
+                }
+                return false;
+            }
+        };
+        mAlert.getButton(BUTTON_POSITIVE).setOnTouchListener(filterTouchListener);
     }
 
     private class UsbDisconnectedReceiver extends BroadcastReceiver {