Support the rich content for accessibility service (1/n)

Goal: 1. let third party developer can use html text that include from their local image file and
         animated image instead of only plain text to rich their content.
      2. Avoid malicious links made by third party developer

Action: 1. Add html, static text, and animated image preferences.
        2. Add android:AnimatedImageDrawable, and android:htmlDescription attributes.
        3. Fine-tune interface and integration
        4. Add custom tag filter

Bug: 136292241
Test: Maunal & make RunSettingsRoboTests
Change-Id: I82cd5319efb7faa1ff7e8354a279828fce5135b8

tests/robotests/src/com/android/settings/accessibility/HtmlTextPreferenceTest.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2019 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.accessibility;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.Context;
+import android.text.Editable;
+import android.text.Html;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.widget.TextView;
+
+import androidx.preference.PreferenceViewHolder;
+
+import com.android.settings.R;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+import org.xml.sax.XMLReader;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/** Tests for {@link HtmlTextPreference} */
+@RunWith(RobolectricTestRunner.class)
+public final class HtmlTextPreferenceTest {
+
+    private HtmlTextPreference mHtmlTextPreference;
+    private PreferenceViewHolder mPreferenceViewHolder;
+    private String mHandledTag;
+    private final Html.TagHandler mTagHandler = new Html.TagHandler() {
+        @Override
+        public void handleTag(boolean opening, String tag, Editable editable, XMLReader xmlReader) {
+            mHandledTag = tag;
+        }
+    };
+
+    @Before
+    public void setUp() {
+        final Context context = RuntimeEnvironment.application;
+        mHtmlTextPreference = new HtmlTextPreference(context);
+
+        final LayoutInflater inflater = LayoutInflater.from(context);
+        final View view =
+                inflater.inflate(R.layout.preference_static_text, null);
+        mPreferenceViewHolder = PreferenceViewHolder.createInstanceForTests(view);
+    }
+
+    @Test
+    public void testUnsupportedTagList_keepRealContentWithoutTag() {
+        final List<String> testUnsupportedTagList = new ArrayList<>();
+        testUnsupportedTagList.add("testTag");
+        final String testStr = "<testTag>Real description</testTag>";
+        final String expectedStr = "Real description";
+        final String expectedTag = "unsupportedtag1";
+
+        mHtmlTextPreference.setUnsupportedTagList(testUnsupportedTagList);
+        mHtmlTextPreference.setSummary(testStr);
+        mHtmlTextPreference.setTagHandler(mTagHandler);
+        mHtmlTextPreference.onBindViewHolder(mPreferenceViewHolder);
+
+        final TextView summaryView = mPreferenceViewHolder.itemView.findViewById(
+                android.R.id.summary);
+        assertThat(summaryView.getText().toString()).isEqualTo(expectedStr);
+        assertThat(mHandledTag).isEqualTo(expectedTag);
+    }
+}