IE CKEDITOR.editor.resize throw 'invalid argument' when no height value is specified

[Michael Camden]

Steps to reproduce:

1. Go to ckeditor.com/demo
2. Open a javascript console and execute, 'CKEDITOR.instances.editor1.resize(50);'

The height value that is assigned becomes 'NaNpx' which is an invalid argument. Likely this has to due with line 345 in theme.js.

345 - contents.setStyle( 'height', Math.max( height - delta, 0 ) + 'px' );

In this case since height is undefined, Math.max(undefined - delta,0) returns NaN. NaN + 'px' = 'NaNpx'. Other browsers must handle this error more gracefully than IE. A simple conditional statement should fix this problem.

344 - if(height) {
345 - contents.setStyle( 'height', Math.max( height - delta, 0 ) + 'px' );
346 - }

[Jakub Ś]

Reproducible from CKEditor 3.0 in IE8, IE7, IE6.

IE9 as well as other browsers didn't throw any errors in this case.

[Jakub Ś]

Related to #11613 and still reproducible in IE8.