Is "learning" part of cognitive psychology?
Yes, cognitive psychology incorporates the study of learning. You can see this reflected in other sources that provide general descriptions of cognitive psychology, e.g.:


http://psychology.about.com/od/cognitivepsychology/f/cogpsych.htm
http://psych.rutgers.edu/co
http://infed.org/mobi/the-cognitive-orientation-to-learning/


I'm not recommending these as especially definitive sources; these are just the other three of the first four hits for a Google search of "cognitive psychology learning".

However, cognitive perspectives on learning are not the only perspectives available in psychological theory (see also radical behaviorism).