AccessibilityNodeInfo does not report checkable coreclty.

1. AccessibilitiyNodeInfo's checkable property was not set.

bug:5039205

Change-Id: I083d1c357c6d9875536e66e355c8a33bd580cee6

core/java/android/accessibilityservice/AccessibilityServiceInfo.java

@@ -193,8 +193,6 @@ public class AccessibilityServiceInfo implements Parcelable {
         mId = new ComponentName(serviceInfo.packageName, serviceInfo.name).flattenToShortString();
         mResolveInfo = resolveInfo;
 
-        String settingsActivityName = null;
-        boolean retrieveScreenContent = false;
         XmlResourceParser parser = null;
 
         try {

core/java/android/widget/CompoundButton.java

@@ -217,6 +217,7 @@ public abstract class CompoundButton extends Button implements Checkable {
     @Override
     public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
         super.onInitializeAccessibilityNodeInfo(info);
+        info.setCheckable(true);
         info.setChecked(mChecked);
     }