Include wifi certificates in settings

Deleting wifi certificates isn't supported yet since cascading the
removal back into wifi configs will need some easy way of enumerating
wifi configs first.

Bug: 29208062
Change-Id: I2d9d1ea7e0974701009bfa6ea162b8bc80806639

tests/unit/src/com/android/settings/UserCredentialsTest.java

@@ -17,6 +17,7 @@
 package com.android.settings;
 
 import android.os.Parcel;
+import android.os.Process;
 import android.test.InstrumentationTestCase;
 import android.test.suitebuilder.annotation.SmallTest;
 
@@ -36,7 +37,7 @@ public class UserCredentialsTest extends InstrumentationTestCase {
     @SmallTest
     public void testCredentialIsParcelable() {
         final String alias = "credential-test-alias";
-        Credential c = new Credential(alias);
+        Credential c = new Credential(alias, Process.SYSTEM_UID);
 
         c.storedTypes.add(Credential.Type.CA_CERTIFICATE);
         c.storedTypes.add(Credential.Type.USER_SECRET_KEY);
@@ -47,6 +48,7 @@ public class UserCredentialsTest extends InstrumentationTestCase {
 
         Credential r = Credential.CREATOR.createFromParcel(p);
         assertEquals(c.alias, r.alias);
+        assertEquals(c.uid, r.uid);
         assertEquals(c.storedTypes, r.storedTypes);
     }
 }