WebGLTextures: Make test in resizeImage() more robust.

src/renderers/webgl/WebGLTextures.js

@@ -42,7 +42,9 @@ function WebGLTextures( _gl, extensions, state, properties, capabilities, utils,
 
 			// only perform resize for certain image types
 
-			if ( image instanceof HTMLImageElement || image instanceof HTMLCanvasElement || image instanceof ImageBitmap ) {
+			if ( ( typeof HTMLImageElement !== 'undefined' && image instanceof HTMLImageElement ) ||
+				( typeof HTMLCanvasElement !== 'undefined' && image instanceof HTMLCanvasElement ) ||
+				( typeof ImageBitmap !== 'undefined' && image instanceof ImageBitmap ) ) {
 
 				var floor = needsPowerOfTwo ? _Math.floorPowerOfTwo : Math.floor;