Add getTextSize() for CButton

Summary: 9c5062147a introduced the `getTextSize()` to all GUIObjects for
getting the rendered size of a text. 8190293f8b made it only available
to CText. `getTextSize()` can also be useful for CButtons so this diff
adds the function back to CButtons. There seem to be no other GUIObjects
besiders CText and CButton where `getTextSize()` makes sense.

Reviewed By: wraitii
Differential Revision: https://code.wildfiregames.com/D3195
This was SVN commit r24378.

source/gui/ObjectTypes/CButton.cpp

@@ -21,6 +21,7 @@
 
 #include "gui/CGUI.h"
 #include "gui/CGUIText.h"
+#include "gui/Scripting/JSInterface_GUIProxy.h"
 #include "gui/SettingTypes/CGUIColor.h"
 
 CButton::CButton(CGUI& pGUI)
@@ -117,3 +118,24 @@ const CGUIColor& CButton::ChooseColor()
 
 	return m_TextColorOver || m_TextColor;
 }
+
+void CButton::CreateJSObject()
+{
+	ScriptRequest rq(m_pGUI.GetScriptInterface());
+
+	js::ProxyOptions options;
+	options.setClass(&JSI_GUIProxy<CButton>::ClassDefinition());
+
+	JS::RootedValue cppObj(rq.cx), data(rq.cx);
+	cppObj.get().setPrivate(this);
+	data.get().setPrivate(GetGUI().GetProxyData(&JSI_GUIProxy<CButton>::Singleton()));
+	m_JSObject.init(rq.cx, js::NewProxyObject(rq.cx, &JSI_GUIProxy<CButton>::Singleton(), cppObj, nullptr, options));
+	js::SetProxyReservedSlot(m_JSObject, 0, data);
+}
+
+void CButton::getTextSize(ScriptInterface& scriptInterface, JS::MutableHandleValue ret)
+{
+	ScriptRequest rq(scriptInterface);
+	UpdateText();
+	ScriptInterface::ToJSVal(rq, ret, m_GeneratedTexts[0].GetSize());
+}

source/gui/ObjectTypes/CButton.h

@@ -28,6 +28,8 @@ class CButton : public IGUIObject, public IGUITextOwner, public IGUIButtonBehavi
 {
 	GUI_OBJECT(CButton)
 
+	friend JSI_GUIProxy<CButton>;
+
 public:
 	CButton(CGUI& pGUI);
 	virtual ~CButton();
@@ -69,6 +71,10 @@ protected:
 	 */
 	CPos m_TextPos;
 
+	virtual void CreateJSObject();
+
+	void getTextSize(ScriptInterface& scriptInterface, JS::MutableHandleValue ret);
+
 	// Settings
 	float m_BufferZone;
 	i32 m_CellID;