Enforce password complexity in lockscreen setting

Enforce a lock screen that adheres with the required complexity set by
the admin.

This is done by querying the DevicePolicyManager for the complexity set
for the given user, and merging it with the complexity from the "change
lock screen" intent (if any).

If the admin sets a higher complexity requirement than the app
triggering the lock screen change request, then the admin-set complexity
is enforced and the user is not shown information about the requesting
app.

Bug: 165573442
Test: Manually, set complexity using TestDPC and see it applies.
Test: m RunSettingsRoboTests ROBOTEST_FILTER=com.android.settings.password.ChooseLockGenericTest
Test: m RunSettingsRoboTests ROBOTEST_FILTER=com.android.settings.password.ChooseLockPasswordTest
Change-Id: If3f24f7430bdcbcd34265339f7d2a1ff82a44fc1

tests/robotests/src/com/android/settings/testutils/shadow/ShadowLockPatternUtils.java

@@ -18,19 +18,31 @@ package com.android.settings.testutils.shadow;
 
 import android.app.admin.DevicePolicyManager;
 import android.content.ComponentName;
+import android.os.UserHandle;
 
 import com.android.internal.widget.LockPatternUtils;
 import com.android.internal.widget.LockscreenCredential;
 
 import org.robolectric.annotation.Implementation;
 import org.robolectric.annotation.Implements;
+import org.robolectric.annotation.Resetter;
 
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 @Implements(LockPatternUtils.class)
 public class ShadowLockPatternUtils {
 
     private static boolean sDeviceEncryptionEnabled;
+    private static Map<Integer, Integer> sUserToComplexityMap = new HashMap<>();
+
+
+    @Resetter
+    public static void reset() {
+        sUserToComplexityMap.clear();
+        sDeviceEncryptionEnabled = false;
+    }
 
     @Implementation
     protected boolean hasSecureLockScreen() {
@@ -76,4 +88,18 @@ public class ShadowLockPatternUtils {
     protected boolean checkPasswordHistory(byte[] passwordToCheck, byte[] hashFactor, int userId) {
         return false;
     }
+
+    @Implementation
+    public @DevicePolicyManager.PasswordComplexity int getRequestedPasswordComplexity(int userId) {
+        return sUserToComplexityMap.getOrDefault(userId,
+                DevicePolicyManager.PASSWORD_COMPLEXITY_NONE);
+    }
+
+    public static void setRequiredPasswordComplexity(int userId, int complexity) {
+        sUserToComplexityMap.put(userId, complexity);
+    }
+
+    public static void setRequiredPasswordComplexity(int complexity) {
+        setRequiredPasswordComplexity(UserHandle.myUserId(), complexity);
+    }
 }