Merge pull request #923 from wordpress-mobile/issue/831-re-instante-style-null-check

Fix `parentStyle must not be null`

Author: maxme

aztec/src/main/kotlin/org/wordpress/aztec/plugins/CssUnderlinePlugin.kt

@@ -45,7 +45,9 @@ class CssUnderlinePlugin(
                     if (hiddenSpan.TAG == SPAN_TAG) {
                         val parentStyle = hiddenSpan.attributes.getValue(CssStyleFormatter.STYLE_ATTRIBUTE)
                         val childStyle = calypsoUnderlineSpan.attributes.getValue(CssStyleFormatter.STYLE_ATTRIBUTE)
-                        hiddenSpan.attributes.setValue(CssStyleFormatter.STYLE_ATTRIBUTE, CssStyleFormatter.mergeStyleAttributes(parentStyle, childStyle))
+                        if (parentStyle != null && childStyle != null) {
+                            hiddenSpan.attributes.setValue(CssStyleFormatter.STYLE_ATTRIBUTE, CssStyleFormatter.mergeStyleAttributes(parentStyle, childStyle))
+                        }
 
                         // remove the extra child span
                         spannable.removeSpan(calypsoUnderlineSpan)