Auto merge of #359 - vvilhonen:vvilhonen/expose-htmlserializer-for-customizing-output, r=jdm

Expose HtmlSerializer for customizing output

This allows 3rd party crates to customize the output without duplicating all the serialization logic. I'm using it myself to pretty print transformed html, where I don't care that the added whitespace changes the meaning of the document.

Author: bors-servo

html5ever/src/serialize/mod.rs

@@ -55,8 +55,8 @@ struct ElemInfo {
     processed_first_child: bool,
 }
 
-struct HtmlSerializer<Wr: Write> {
-    writer: Wr,
+pub struct HtmlSerializer<Wr: Write> {
+    pub writer: Wr,
     opts: SerializeOpts,
     stack: Vec<ElemInfo>,
 }
@@ -74,7 +74,7 @@ fn tagname(name: &QualName) -> LocalName {
 }
 
 impl<Wr: Write> HtmlSerializer<Wr> {
-    fn new(writer: Wr, opts: SerializeOpts) -> Self {
+    pub fn new(writer: Wr, opts: SerializeOpts) -> Self {
         let html_name = match opts.traversal_scope {
             TraversalScope::IncludeNode | TraversalScope::ChildrenOnly(None) => None,
             TraversalScope::ChildrenOnly(Some(ref n)) => Some(tagname(n)),