[Fingerprint] Fix link accessibility

Copied ExploreByTouchHelper, LinkAccessibilityHelper and LinkTextView
from setup wizard and switched fingerprint_settings_footer to use
LinkTextView, so that users can navigate to the link in TalkBack
mode.

Bug: 24343933
Change-Id: I0ff0c054510dfef4263ea223cb0044a4bddf321f

src/com/android/settings/widget/LinkTextView.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * 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 com.android.settings.widget;
+
+import android.content.Context;
+import android.support.annotation.NonNull;
+import android.util.AttributeSet;
+import android.view.MotionEvent;
+import android.widget.TextView;
+
+/**
+ * Copied from setup wizard.
+ */
+public class LinkTextView extends TextView {
+
+    private LinkAccessibilityHelper mAccessibilityHelper;
+
+    public LinkTextView(Context context) {
+        this(context, null);
+    }
+
+    public LinkTextView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        mAccessibilityHelper = new LinkAccessibilityHelper(this);
+        setAccessibilityDelegate(mAccessibilityHelper);
+    }
+
+    @Override
+    protected boolean dispatchHoverEvent(@NonNull MotionEvent event) {
+        if (mAccessibilityHelper.dispatchHoverEvent(event)) {
+            return true;
+        }
+        return super.dispatchHoverEvent(event);
+    }
+}