Remove unused QgsCoordinateTransform::readXml/writeXml methods

These methods are not used in master and are of questionable
value. Better to serialise the source and dest crs separately
and create the transform when required

doc/api_break.dox

@@ -930,7 +930,7 @@ plugins calling these methods will need to be updated.
 - 'p' argument in transform() has been renamed to 'point', 'theRect' to 'rectangle', 'poly' to 'polygon'
 - setDestCRSID has been removed, use setDestinationCrs() instead
 - 'theNode', 'theDoc' parameters in readXML and writeXML have been renamed to 'node' and 'document' respectively
-- readXML() and writeXML() have been renamed to readXml() and writeXml() for consistency
+- readXML() and writeXML() have been removed.
 
 
 QgsCoordinateTransformCache        {#qgis_api_break_3_0_QgsCoordinateTransformCache}

src/core/qgscoordinatetransform.cpp

@@ -574,44 +574,6 @@ bool QgsCoordinateTransform::isShortCircuited() const
   return !d->mIsValid || d->mShortCircuit;
 }
 
-bool QgsCoordinateTransform::readXml( const QDomNode &node )
-{
-  d.detach();
-
-  QgsDebugMsg( "Reading Coordinate Transform from xml ------------------------!" );
-
-  QDomNode mySrcNode = node.namedItem( QStringLiteral( "sourcesrs" ) );
-  d->mSourceCRS.readXml( mySrcNode );
-
-  QDomNode myDestNode = node.namedItem( QStringLiteral( "destinationsrs" ) );
-  d->mDestCRS.readXml( myDestNode );
-
-  d->mSourceDatumTransform = node.toElement().attribute( QStringLiteral( "sourceDatumTransform" ), QStringLiteral( "-1" ) ).toInt();
-  d->mDestinationDatumTransform = node.toElement().attribute( QStringLiteral( "destinationDatumTransform" ), QStringLiteral( "-1" ) ).toInt();
-
-  return d->initialize();
-}
-
-bool QgsCoordinateTransform::writeXml( QDomNode &node, QDomDocument &doc ) const
-{
-  QDomElement myNodeElement = node.toElement();
-  QDomElement myTransformElement = doc.createElement( QStringLiteral( "coordinatetransform" ) );
-  myTransformElement.setAttribute( QStringLiteral( "sourceDatumTransform" ), QString::number( d->mSourceDatumTransform ) );
-  myTransformElement.setAttribute( QStringLiteral( "destinationDatumTransform" ), QString::number( d->mDestinationDatumTransform ) );
-
-  QDomElement mySourceElement = doc.createElement( QStringLiteral( "sourcesrs" ) );
-  d->mSourceCRS.writeXml( mySourceElement, doc );
-  myTransformElement.appendChild( mySourceElement );
-
-  QDomElement myDestElement = doc.createElement( QStringLiteral( "destinationsrs" ) );
-  d->mDestCRS.writeXml( myDestElement, doc );
-  myTransformElement.appendChild( myDestElement );
-
-  myNodeElement.appendChild( myTransformElement );
-
-  return true;
-}
-
 const char *finder( const char *name )
 {
   QString proj;

src/core/qgscoordinatetransform.h

@@ -279,23 +279,6 @@ class CORE_EXPORT QgsCoordinateTransform
     //!initialize is used to actually create the Transformer instance
     void initialize();
 
-    /**
-     * Restores state from the given Dom node.
-     * \param node The node from which state will be restored
-     * \returns bool True on success, False on failure
-     * \see writeXml()
-     */
-    bool readXml( const QDomNode &node );
-
-    /**
-     * Stores state to the given Dom node in the given document
-     * \param node The node in which state will be restored
-     * \param document The document in which state will be stored
-     * \returns bool True on success, False on failure
-     * \see readXml()
-     */
-    bool writeXml( QDomNode &node, QDomDocument &document ) const;
-
   private:
 
     static void searchDatumTransform( const QString &sql, QList< int > &transforms );