Bug 207268 Add visibility option for plot within axes
For chart with axes, we should make plot within axes invisible. Meantime, other plots, such as axes, legend and title, should be visible. This enhancement doesn't include UI change, and it is required for cross tab integration.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/model/layout/ClientArea.java
* 
	 * <!-- end-model-doc -->
	 * 
	 * @return the value of the '<em>Background</em>' containment reference.
	 * @see #setBackground(Fill)
	 * @see org.eclipse.birt.chart.model.layout.LayoutPackage#getClientArea_Background()
	 * @model containment="true" resolveProxies="false" required="true"
	 * @generated
	 */
	Fill getBackground( );
	/**
	 * Sets the value of the '{@link org.eclipse.birt.chart.model.layout.ClientArea#getBackground <em>Background</em>}' containment reference.
	 * <!-- begin-user-doc --> <!-- end-user-doc -->
	 * @param value the new value of the '<em>Background</em>' containment reference.
	 * @see #getBackground()
	 * @generated
	 */
	void setBackground( Fill value );
	/**
	 * Returns the value of the '<em><b>Outline</b></em>' containment reference. <!-- begin-user-doc --> Gets the
	 * attributes of the border for the client area. <!-- end-user-doc --> <!-- begin-model-doc -->
	 * 
	 * Holds the outline information for the client area.
	 * 
	 * <!-- end-model-doc -->
	 * 
	 * @return the value of the '<em>Outline</em>' containment reference.
	 * @see #setOutline(LineAttributes)
	 * @see org.eclipse.birt.chart.model.layout.LayoutPackage#getClientArea_Outline()
	 * @model containment="true" resolveProxies="false" required="true"