Announce text on ReaderModeInfoBar as a Button for accessibility

Use a fake Button class for the TextViews on Reader Mode Infobar, so
that it can be announced as a button with TalkBack.

Bug: 773763
Change-Id: I0a3f62a0752604e7fe94d9bc61d8b69edb4be8d0
Reviewed-on: https://chromium-review.googlesource.com/713755
Commit-Queue: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Reviewed-by: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#509241}

chrome/android/java/src/org/chromium/chrome/browser/infobar/ReaderModeInfoBar.java

@@ -6,9 +6,13 @@ package org.chromium.chrome.browser.infobar;
 
 import static android.view.View.IMPORTANT_FOR_ACCESSIBILITY_NO;
 
+import android.content.Context;
 import android.util.TypedValue;
 import android.view.Gravity;
 import android.view.View;
+import android.view.accessibility.AccessibilityEvent;
+import android.view.accessibility.AccessibilityNodeInfo;
+import android.widget.Button;
 import android.widget.ImageView;
 import android.widget.TextView;
 
@@ -40,6 +44,27 @@ public class ReaderModeInfoBar extends InfoBar {
         }
     };
 
+    /**
+     * Fake Button class, used so TextViews can announce themselves as Buttons, for accessibility.
+     */
+    public static class AccessibleTextView extends TextView {
+        public AccessibleTextView(Context context) {
+            super(context);
+        }
+
+        @Override
+        public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
+            super.onInitializeAccessibilityEvent(event);
+            event.setClassName(Button.class.getName());
+        }
+
+        @Override
+        public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
+            super.onInitializeAccessibilityNodeInfo(info);
+            info.setClassName(Button.class.getName());
+        }
+    }
+
     /**
      * Default constructor.
      */
@@ -59,7 +84,7 @@ public class ReaderModeInfoBar extends InfoBar {
 
     @Override
     protected void createCompactLayoutContent(InfoBarCompactLayout layout) {
-        TextView prompt = new TextView(getContext());
+        TextView prompt = new AccessibleTextView(getContext());
         if (ChromeFeatureList.isEnabled(ChromeFeatureList.ALLOW_READER_FOR_ACCESSIBILITY)) {
             prompt.setText(R.string.reader_view_text_alt);
         } else {