Make SslErrorHandler ctor public/@hide.

Allow WebViewProvider implementations to subclass SslErrorHandler
but at the same time maintain API compatibility by @hide'ing the
constructor.

Bug: 6238802
Change-Id: I5de268364ed74e59f62439b8612ab682656a7906

core/java/android/webkit/SslErrorHandler.java

@@ -26,9 +26,9 @@ import android.os.Handler;
 public class SslErrorHandler extends Handler {
 
     /**
-     * Package-private constructor needed for API compatibility.
+     * @hide Only for use by WebViewProvider implementations.
      */
-    SslErrorHandler() {}
+    public SslErrorHandler() {}
 
     /**
      * Proceed with the SSL certificate.