DO NOT MERGE KeyChain protect against overlays.

Set setFilterTouchesWhenObsucred on positive confirmation button.

Test: N/A
Bug: 199754277
Change-Id: I096afafb74b69e86e82f89f6121ba52d65c99564
(cherry picked from commit 2b7ea9710d2069f9768cc3c2350df74b60f9ecbf)
diff --git a/src/com/android/keychain/KeyChainActivity.java b/src/com/android/keychain/KeyChainActivity.java
index 8fc70ea..f8cb0d3 100644
--- a/src/com/android/keychain/KeyChainActivity.java
+++ b/src/com/android/keychain/KeyChainActivity.java
@@ -394,6 +394,9 @@
                 finish(null);
             }
         });
+        dialog.create();
+        // Prevents screen overlay attack.
+        dialog.getButton(DialogInterface.BUTTON_POSITIVE).setFilterTouchesWhenObscured(true);
         dialog.show();
     }