Implemented XMLSerializer in PrivateScript.

Source/core/xml/XMLSerializer.js

Index: Source/core/xml/XMLSerializer.js
diff --git a/Source/core/xml/XMLSerializer.js b/Source/core/xml/XMLSerializer.js
new file mode 100644
index 0000000000000000000000000000000000000000..d70cf16472eeeff19cfda86a8ff4e85db3eba10f
--- /dev/null
+++ b/Source/core/xml/XMLSerializer.js
@@ -0,0 +1,371 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+"use strict";

[yosin_UTC9, 2014/09/03 03:35:02]

Let's use one kind of quote.
I suggest to use single-quote as of Google JS coding style:
https://google-styleguide.googlecode.com/svn/trunk/javascriptguide.xml

Note: JS in Chromium follow this:
http://dev.chromium.org/developers/web-development-style-guide

[tasak, 2014/09/03 09:38:00]

Done.

+
+installClass("XMLSerializer", function(XMLSerializerPrototype) {
+
+    var _EMPTY = '';
+
+    var _XML_NAMESPACE_URI = 'http://www.w3.org/XML/1998/namespace';
+    var _XLINK_NAMESPACE_URI = 'http://www.w3.org/1999/xlink';
+    var _XMLNS_NAMESPACE_URI = 'http://www.w3.org/2000/xmlns';
+    var _HTML_NAMESPACE_URI = 'http://www.w3.org/1999/xhtml';
+
+    var _SERIALIZATION_TYPE_AS_OWNER_DOCUMENT = 0;
+    var _SERIALIZATION_TYPE_FORCED_XML = 1;
+
+    function escape(text) {
+        return text.replace(/&/g, '&amp;').replace(/\u0022/g, '&quot;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
+    }
+
+    function validateURI(uri) {
+        if (!uri)

[yosin_UTC9, 2014/09/03 03:35:02]

nit: return uri === '' ? '' : uri.replace(/\/$/g, '');

[tasak, 2014/09/03 09:38:00]

We need to consier the case that uri is null.

So this should be "return uri ? uri.replace(...) : '';".

+            return uri;
+        return uri.replace(/\/$/g, '');
+    }
+
+    function cloneNamespace(obj) {

[yosin_UTC9, 2014/09/03 03:35:01]

This function make clone of object, not sure why we call |cloneNamespace|.

[tasak, 2014/09/03 09:38:00]

When we visit child nodes, one of the child nodes might update namespaces.
However, other child nodes should not be affected by the update.

+        var clone = {};

[yosin_UTC9, 2014/09/03 03:35:01]

nit: return Object.create(obj);

[tasak, 2014/09/03 09:38:00]

I think, this doesn't work.

+        for (var i in obj)
+            clone[i] = obj[i];
+        return clone;
+    }
+
+    function isTemplateElement(node) {
+        if (isHTMLElement(node) && node.tagName.toLowerCase() == 'template')

[yosin_UTC9, 2014/09/03 03:35:01]

nit: Just use |return| statement.
nit: We don't need to use |toLowerCase()|, just compare to 'TEMPLATE'.
nit: You can use 'node.nodeName', if so, you don't need to call isHTMLElement().

[tasak, 2014/09/03 09:38:00]

I don't think so. If we always compare with 'TEMPLATE',
LayoutTests/fast/dom/HTMLTemplateElement/xhtml-parsing-and-serialization.xml
fails.
xml document also has an element whose tagname is 'template' and whose namespace
uri is not html. In this case, we should not treat the element as
HTMLTemplateElement.

+            return true;
+        return false;
+    }
+
+    function generatePrefix(namespaces) {
+        var _MAX_RETRY = 10;
+        for (var count = 0; count < _MAX_RETRY; ++count) {
+            var candidate = 'ns' + Date.now();

[yosin_UTC9, 2014/09/03 03:35:01]

We should have closed variable, rather than using current time as unique
counter.

var uniquePrefixCounter = 0;
function generatePrefix(namespaces) {
  ...
  ++uniquePrefixCounter;
  var candidate = 'ns' + uniquePrefixCounter;
  ...
}

[tasak, 2014/09/03 09:38:00]

I tried another approach.

+            if (!namespaces[candidate])
+                return candidate;
+        }
+        return null;
+    }
+
+    function qualifiedTagName(node) {
+        var tagName = node.tagName.toLowerCase();

[yosin_UTC9, 2014/09/03 03:35:02]

not obvious what you want to accomplish.
Can we use node.namespaceURI for checking qualified name?

[tasak, 2014/09/03 09:38:00]

I updated.
If a given node is HTMLElement, we should use node.tagName.toLowerCase().
Otherwise, we should just return node.tagName.

+        if (tagName != node.tagName && node.tagName.toUpperCase() != node.tagName)
+            tagName = node.tagName;
+        return tagName;
+    }
+
+    function attributeIsInSerializedNamespace(attr) {
+        var namespaceURI = validateURI(attr.namespaceURI);
+        if (namespaceURI == _XML_NAMESPACE_URI ||

[yosin_UTC9, 2014/09/03 03:35:02]

We should have |Set| which member is well know namespace URI, rather than
serialize of equality checks.

[tasak, 2014/09/03 09:38:00]

Done.

+            namespaceURI == _XLINK_NAMESPACE_URI ||
+            namespaceURI == _XMLNS_NAMESPACE_URI)
+            return true;
+        return false;
+    }
+
+    function appendNamespace(prefix, namespaceURI, namespaces) {
+        if (!namespaceURI)
+            return '';
+
+        var result = '';
+        var lookupKey = _EMPTY;
+        if (prefix)
+            lookupKey = prefix;
+        if (namespaces[lookupKey] != namespaceURI) {
+            namespaces[lookupKey] = namespaceURI;
+            result += ' xmlns';
+            if (prefix) {

[yosin_UTC9, 2014/09/03 03:35:01]

nit: No need to have "{}"

[tasak, 2014/09/03 09:38:00]

Done.

+                result += ':' + prefix;
+            }
+            result += '=\"' + namespaceURI + '"';
+        }
+        return result;
+    }
+
+    function shouldAddNamespaceAttribute(attr, node) {
+        if (!attr.namespaceURI)
+            return false;
+        if (!attr.prefix)
+            return true;
+        if (!node.hasAttribute('xmlns:' + attr.prefix))
+            return true;
+        return false;
+    }
+
+    function shouldAddNamespaceElement(node, namespaces) {
+        var prefix = node.prefix;
+        if (!node.prefix) {
+            if (node.hasAttribute('xmlns')) {
+                namespaces[_EMPTY] = node.namespaceURI;
+                return false;
+            }
+            return true;
+        }
+        if (!node.hasAttribute('xmlns:' + node.prefix))
+            return true;
+        return false;
+    }
+
+    function isHTMLElement(node) {
+        if (node.nodeType != Node.ELEMENT_NODE)
+            return false;
+
+        while (node) {

[yosin_UTC9, 2014/09/03 03:35:01]

nit: it is better to use for statement

for (var runner = node; node; node = node.parentNode) {
  ...
}

[tasak, 2014/09/03 09:38:00]

Done.

+            if (node.nodeType == Node.ELEMENT_NODE) {
+                var namespaceURI = validateURI(node.namespaceURI);
+                if (namespaceURI)
+                    return namespaceURI == _HTML_NAMESPACE_URI;
+            }
+            node = node.parentNode;
+        }
+        return false;
+    }
+
+    function elementCannotHaveEndTag(node) {

[yosin_UTC9, 2014/09/03 03:35:01]

nit: HTML5 use term "Tag ommission in text/html"
http://www.whatwg.org/specs/web-apps/current-work/multipage/semantics.html#th...

So, better name is isEndTagOmissible(element)

[tasak, 2014/09/03 09:38:00]

Done.

+        if (node.nodeType != Node.ELEMENT_NODE)
+            return false;
+        var _IE_FORBIDS_TAG = {'area':true, 'base':true, 'basefont':true, 'br':true, 'col':true, 'embed':true,
+                               'frame':true, 'hr':true, 'image':true, 'img':true, 'input':true, 'link':true,
+                               'meta':true, 'param':true, 'source':true, 'wbr':true};
+        var tagName = node.tagName.toLowerCase();

[yosin_UTC9, 2014/09/03 03:35:01]

nit: To avoid string object construction, we should use upper case letters for
key.

[tasak, 2014/09/03 09:38:00]

I found layout test failure if using upper case letters for key and removing
tagName.toLowerCase().

+        if (_IE_FORBIDS_TAG[tagName])
+            return true;
+        return false;
+    }
+
+    XMLSerializerPrototype.serializeAsHTMLDocument = function(node) {

[yosin_UTC9, 2014/09/03 03:35:01]

I suggest to use
Object.defineProperties(XMLSerializePrototype, {
  serializeAsHTMLDocument: {value: serializeAsHTMLDocument},
  ...
});

In this way, you can see function name in stack trace.

[tasak, 2014/09/03 09:38:00]

I'm not sure whether we allow users to see internal function names in stack
trace or not.

[yosin_UTC9, 2014/09/04 00:58:44]

When you use this JS file in standalone environment, e.g. debugging JS w/o
Blink-In-JS, we can see function names in inspector.

As adamb@ said, it is better that JS code for Blink-In-JS works in other
browsers, including Chrome w/o Blink-In-JS.

+        if (this.serialization_type_ == _SERIALIZATION_TYPE_FORCED_XML)
+            return false;
+        return node.ownerDocument && (node.ownerDocument instanceof HTMLDocument);
+    }
+
+    XMLSerializerPrototype.serializeAttribute = function(node, attr, namespaces) {
+        var documentIsHTML = this.serializeAsHTMLDocument(node);
+        var result = '';
+
+        var attrPrefix = attr.prefix;
+        var attrName = attr.localName;
+        if (documentIsHTML && !attributeIsInSerializedNamespace(attr)) {
+            result += ' ' + attr.localName;
+        } else {
+            var namespaceURI = validateURI(attr.namespaceURI);
+            if (namespaceURI == _XMLNS_NAMESPACE_URI) {
+                if (!attr.prefix && attr.localName != 'xmlns')
+                    attrPrefix = 'xmlns';
+                if (namespaces) {
+                    var lookupKey = _EMPTY;
+                    if (attr.prefix)
+                        lookupKey = attr.localName;
+                    namespaces[lookupKey] = attr.value;
+                }
+            } else if (namespaceURI == _XML_NAMESPACE_URI) {
+                if (!attr.prefix)
+                    attrPrefix = 'xml';
+            } else {
+                if (namespaceURI == _XLINK_NAMESPACE_URI) {
+                    if (!attr.prefix)
+                        attrPrefix = 'xlink';
+                }
+                if (namespaces && shouldAddNamespaceAttribute(attr, node)) {
+                    if (!attrPrefix) {
+                        for (var i in namespaces) {
+                            if (namespaces[i] == namespaceURI && i) {
+                                attrPrefix = i;
+                                break;
+                            }
+                        }
+                        if (!attrPrefix)
+                            attrPrefix = generatePrefix(namespaces);
+                    }
+                    result += appendNamespace(attrPrefix, namespaceURI, namespaces);
+                }
+            }
+            if (attrPrefix) {
+                result += ' ' + attrPrefix + ':' + attrName;
+            } else {
+                result += ' ' + attrName;
+            }
+        }
+        if (attr.value)
+            result += '="' + escape(String(attr.value)) + '"';
+        return result;
+    }
+
+    XMLSerializerPrototype.serializeAttributes = function(node, namespaces) {
+        var attributes = node.attributes;
+        if (!attributes)
+            return '';
+
+        var sink = '';
+        var attrs = [];
+        for (var index = 0; index < attributes.length; ++index)
+           attrs.push(attributes[index]);
+
+        var serializer = this;
+        attrs.sort(function(a, b) {
+            return a.name <= b.name ? -1 : 0;
+        }).forEach(function(attr) {
+            if (attr.name.indexOf('_moz') == 0)
+                return;
+            sink += serializer.serializeAttribute(node, attr, namespaces);
+        });
+        return sink;
+    }
+
+    XMLSerializerPrototype.serializeOpenTag = function(node, namespaces) {
+        var sink = '<' + qualifiedTagName(node);
+        if (!this.serializeAsHTMLDocument(node) && namespaces && shouldAddNamespaceElement(node, namespaces))
+            sink += appendNamespace(node.prefix, node.namespaceURI, namespaces);
+        return sink;
+    }
+
+    XMLSerializerPrototype.serializeCloseTag = function(node, namespaces) {
+        var sink = '';
+        if (this.shouldSelfClose(node)) {
+            if (isHTMLElement(node))
+                sink += ' ';
+            sink += '/';
+        }
+        sink += '>';
+        return sink;
+    }
+
+    XMLSerializerPrototype.serializeElement = function(node, namespaces) {
+        var sink = this.serializeOpenTag(node, namespaces);
+
+        sink += this.serializeAttributes(node, namespaces);
+        sink += this.serializeCloseTag(node, namespaces);
+        return sink;
+    }
+
+    XMLSerializerPrototype.serializeText = function(node) {
+        return escape(node.nodeValue);
+    }
+
+    XMLSerializerPrototype.serializeComment = function(node) {
+        return '<!--' + node.nodeValue + '-->';
+    }
+
+    XMLSerializerPrototype.serializeDocument = function(node) {
+        if (!node.hasXMLDeclaration)
+            return '';
+
+        var s = '<?xml';
+        if (node.xmlVersion)
+            s += ' version="' + node.xmlVersion + '"';
+        if (node.xmlEncoding)
+            s += ' encoding="' + node.xmlEncoding + '"';
+        if (node.isXMLStandaloneSpecified) {
+            s += ' standalone="'
+            if (node.xmlStandalone) {
+                s += 'yes';
+            } else {
+                s += 'no';
+            }
+            s += '"';
+        }
+        s += '?>';
+        return s;
+    }
+
+    XMLSerializerPrototype.serializeDocumentType = function(node) {
+        var s = '<!DOCTYPE ' + node.name;
+        if (node.publicId) {
+            s += ' PUBLIC "' + node.publicId + '"';
+            if (node.systemId)
+                s += ' "' + node.systemId + '"';
+        }
+        s += '>';
+        return s;
+    }
+
+    XMLSerializerPrototype.serializeProcessingInstruction = function(node) {
+        var s = '<?' + node.target;
+        if (node.nodeValue)
+            s += ' ' + node.nodeValue;
+        s += '?>';
+        return s;
+    }
+
+    XMLSerializerPrototype.serializeCDataSection = function(node) {
+        return '<![CDATA[' + node.nodeValue + ']]>';
+    }
+
+    XMLSerializerPrototype.serializeStartTag = function(node, namespaces) {
+        if (node.nodeType == Node.TEXT_NODE) {
+            return this.serializeText(node);
+        } else if (node.nodeType == Node.COMMENT_NODE) {
+            return this.serializeComment(node);
+        } else if (node.nodeType == Node.DOCUMENT_NODE) {
+            return this.serializeDocument(node);
+        } else if (node.nodeType == Node.DOCUMENT_TYPE_NODE) {
+            return this.serializeDocumentType(node);
+        } else if (node.nodeType == Node.DOCUMENT_FRAGMENT_NODE) {
+            return '';
+        } else if (node.nodeType == Node.PROCESSING_INSTRUCTION_NODE) {
+            return this.serializeProcessingInstruction(node);
+        } else if (node.nodeType == Node.ELEMENT_NODE) {
+            return this.serializeElement(node, namespaces);
+        } else if (node.nodeType == Node.CDATA_SECTION_NODE) {
+            return this.serializeCDataSection(node);
+        } else {
+            return '';
+        }
+    }
+
+    XMLSerializerPrototype.shouldSelfClose = function(node) {
+        if (this.serializeAsHTMLDocument(node))
+            return false;
+        if (node.hasChildNodes())
+            return false;
+        if (isTemplateElement(node) && node.content && node.content.hasChildNodes())
+            return false;
+        if (isHTMLElement(node) && !elementCannotHaveEndTag(node))
+            return false;
+        return true;
+    }
+
+    XMLSerializerPrototype.serializeEndTag = function(node) {
+        if (this.shouldSelfClose(node) || (!node.hasChildNodes() && elementCannotHaveEndTag(node)))
+            return '';
+        return '</' + qualifiedTagName(node) + '>';
+    }
+
+    XMLSerializerPrototype.serializeNodesWithNamespaces = function(node, namespaces) {
+        var sink = '';
+        var localNamespaces = cloneNamespace(namespaces);
+        sink += this.serializeStartTag(node, localNamespaces);
+
+        if (!(this.serializeAsHTMLDocument(node) && elementCannotHaveEndTag(node))) {
+            var current = node;
+            if (isTemplateElement(node))
+                current = node.content;
+            current = current.firstChild;
+            while (current) {
+                sink += this.serializeNodesWithNamespaces(current, localNamespaces);
+                current = current.nextSibling;
+            }
+        }
+        if (node.nodeType == Node.ELEMENT_NODE)
+            sink += this.serializeEndTag(node);
+        return sink;
+    }
+
+    XMLSerializerPrototype.serializeNodes = function(node) {
+        var namespaces = {};
+        if (!this.serializeAsHTMLDocument(node))
+            namespaces['xml'] = _XML_NAMESPACE_URI;
+
+        return this.serializeNodesWithNamespaces(node, namespaces);
+    }
+
+    XMLSerializerPrototype.serializeToString = function(root) {
+        if (!root)
+            throw new TypeError("Invalid node value.");
+
+        this.serialization_type_ = _SERIALIZATION_TYPE_FORCED_XML;
+        return this.serializeNodes(root);
+    }
+});