[Gtk] Remove GC.stringExtentInPixel

It simply calls textExtentInPixel(Sting, 0) thus inline it in the 2
places used.

Author: akurtakov

bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/graphics/GC.java

@@ -1871,7 +1871,7 @@ int fixMnemonic (char [] buffer) {
 public int getAdvanceWidth(char ch) {
 	if (handle == 0) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
 	//BOGUS
-	return stringExtentInPixels(new String(new char[]{ch})).x;
+	return textExtentInPixels(new String(new char[]{ch}), 0).x;
 }
 
 /**
@@ -2002,7 +2002,7 @@ public Pattern getBackgroundPattern() {
 public int getCharWidth(char ch) {
 	if (handle == 0) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
 	//BOGUS
-	return stringExtentInPixels(new String(new char[]{ch})).x;
+	return textExtentInPixels(new String(new char[]{ch}), 0).x;
 }
 
 /**
@@ -3789,9 +3789,6 @@ public Point stringExtent(String string) {
 	if (handle == 0) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED);
 	return textExtentInPixels(string, 0);
 }
-Point stringExtentInPixels(String string) {
-	return textExtentInPixels(string, 0);
-}
 
 /**
  * Returns the extent of the given string. Tab expansion and