Android: Fix #354: Don't use StrongBox on Google Pixel devices.

This fix adds transparent data re-encryption in case that SDK determines that device has unreliable StrongBox implementation.

proj-android/PowerAuthLibrary/src/androidTest/java/io/getlime/security/powerauth/keychain/FakeStrongBoxSupport.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2021 Wultra s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.getlime.security.powerauth.keychain;
+
+import io.getlime.security.powerauth.keychain.StrongBoxSupport;
+
+/**
+ * Testing implementation of {@link StrongBoxSupport} interface that can simulate StrongBox support
+ * level during the unit test.
+ */
+public class FakeStrongBoxSupport implements StrongBoxSupport {
+
+    private final boolean isSupported;
+    private final boolean isEnabled;
+
+    /**
+     * Set StrongBox as not supported.
+     */
+    public FakeStrongBoxSupport() {
+        isSupported = false;
+        isEnabled = false;
+    }
+
+    /**
+     * Set any combination of emulated StrongBox support.
+     * @param supported Set StrongBox supported.
+     * @param enabled Set StrongBox enabled.
+     */
+    public FakeStrongBoxSupport(boolean supported, boolean enabled) {
+        isSupported = supported;
+        isEnabled = enabled;
+    }
+
+    @Override
+    public boolean isStrongBoxSupported() {
+        return isSupported;
+    }
+
+    @Override
+    public boolean isStrongBoxEnabled() {
+        return isSupported && isEnabled;
+    }
+}