[gxml] GomElement: added read_from_stream()

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit 5b65663e072ec2220fb6487e5237796590f228e7
Author: Daniel Espinosa <esodan gmail com>
Date:   Tue Feb 14 18:48:31 2017 -0600

    GomElement: added read_from_stream()
    
    Also read_from_file is cacancellable

 gxml/GomElement.vala |   15 ++++++++++++---
 gxml/XParser.vala    |    4 ++--
 2 files changed, 14 insertions(+), 5 deletions(-)
---
diff --git a/gxml/GomElement.vala b/gxml/GomElement.vala
index 9eb52f6..259c7d0 100644
--- a/gxml/GomElement.vala
+++ b/gxml/GomElement.vala
@@ -45,11 +45,20 @@ public class GXml.GomElement : GomNode,
     this.read_from_file (File.new_for_uri (uri));
   }
   /**
-   * Parses an XML file, deserializing it over {@link GomElemen}.
+   * Parses an XML file, deserializing it over {@link GomElement}.
    */
-  public void read_from_file (GLib.File f) throws GLib.Error {
+  public void read_from_file (GLib.File f,
+                      GLib.Cancellable? cancellable = null) throws GLib.Error {
     var parser = new XParser (this);
-    parser.read_file (f, null);
+    parser.read_file (f, cancellable);
+  }
+  /**
+   * Parses an XML over a {@link GLib.InputStream}, deserializing it over {@link GomElement}.
+   */
+  public void read_from_stream (GLib.InputStream istream,
+                      GLib.Cancellable? cancellable = null) throws GLib.Error {
+    var parser = new XParser (this);
+    parser.read_stream (istream, cancellable);
   }
   /**
    * Parses an XML string, deserializing it over {@link GomElemen}.
diff --git a/gxml/XParser.vala b/gxml/XParser.vala
index 7f3be63..8ff97b3 100644
--- a/gxml/XParser.vala
+++ b/gxml/XParser.vala
@@ -52,7 +52,7 @@ public class GXml.XParser : Object, GXml.Parser {
   }
 
   public void write_stream (OutputStream stream,
-                            GLib.Cancellable? cancellable) throws GLib.Error {
+                            GLib.Cancellable? cancellable = null) throws GLib.Error {
     var buf = new Xml.Buffer ();
     tw = Xmlx.new_text_writer_memory (buf, 0);
     if (_node is DomDocument) tw.start_document ();
@@ -94,7 +94,7 @@ public class GXml.XParser : Object, GXml.Parser {
 
 
   public void read_stream (GLib.InputStream istream,
-                          GLib.Cancellable? cancellable) throws GLib.Error {
+                          GLib.Cancellable? cancellable = null) throws GLib.Error {
     var b = new MemoryOutputStream.resizable ();
     b.splice (istream, 0);
 #if DEBUG