Women in Technology

I've enjoyed this series tremendously, but am frustrated I can't implement the last piece. I was doing okay until I tried to compile this:

- (void)webView:(WebView *)sender decidePolicyForNavigationAction:
(NSDictionary *)actionInformation request:(NSURLRequest *)request frame:
(WebFrame *)frame decisionListener:(id<WebPolicyDecisionListener>)listener
{
NSString* urlKey = [[actionInformation objectForKey:WebActionOriginalURLKey] host];

The compiler balks at <WebPolicyDecisionListener> and WebActionOriginalURLKey and I haven't found any other references to these values.

Coming from Java, I don't get the id<WebPolicyDecisionListener> syntax.