KeyChain: Do not allow hiding Cert Install dialog

Do not allow apps to float a window on top of the certificate
installation / naming dialog.

This obscures the CA certificate installation dialog and could be used
to trick a user into installing a CA certificate.

This is fixed by adding the HIDE_NON_SYSTEM_OVERLAY_WINDOWS system
flag when the activity is created (onCreate), so that another activity
starting in the foreground would not be able to obscure the dialog.

Bug: 139017101
Test: Manual, with an app that floats a window.
Change-Id: I637974d2179d6cd266d3762a1464184d2be35bf4
Merged-In: Iff8e678743c3883cf1f7f64390097a768ca00856
(cherry picked from commit 6afaf1846cc28af1ea048ebd55770cb38f77fb19)
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 56ac884..df73092 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -9,6 +9,7 @@
     <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
     <uses-permission android:name="android.permission.MANAGE_USERS" />
     <uses-permission android:name="android.permission.ACCESS_ALL_DOWNLOADS" />
+    <uses-permission android:name="android.permission.HIDE_NON_SYSTEM_OVERLAY_WINDOWS" />
     <application android:label="@string/app_name"
diff --git a/src/com/android/certinstaller/ b/src/com/android/certinstaller/
index 0ec1ce5..f5a72ad 100644
--- a/src/com/android/certinstaller/
+++ b/src/com/android/certinstaller/
@@ -16,6 +16,8 @@
+import static android.view.WindowManager.LayoutParams.PRIVATE_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS;
@@ -94,6 +96,7 @@
     protected void onCreate(Bundle savedStates) {
+        getWindow().addPrivateFlags(PRIVATE_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS);
         mCredentials = createCredentialHelper(getIntent());