Ugh. Unfortunately, just as I had worried, my previous post was taken the wrong way (by TechCrunch). As the long list of caveats were trying to point out, I wasn't trying to frame a Google versus Apple story; aside from the many things wrong with counting commits that I tried to disclaim in that post, there's also a ton of other work that is not even hinted at in that metric.
For example, pretty much every change I've made to WebKit that isn't Chromium-specific has been reviewed by Apple employees; poor Darin Adler has probably invested about 50% of the time I did in reading through the patches I wrote, giving me feedback, and dealing with fallout when they break.
For another example, consider all of the hosting infrastructure (the website, the buildbots, the paperwork of granting people commit access). Or who answers all the questions on the mailing list.
For the record, what I was trying to say with that graph is: isn't it neat that there are so many other contributors to WebKit and that their involvement is growing? There are few (if any) other free software projects in such a healthy state -- the Linux Kernel comes to mind.
If anything, the only competition story in this is that this "coopetition" makes the web evolve faster and in a better way. By virtue of a shared source tree we're compelled to improve Safari/iPhones/Blackberries/etc. as we improve Chrome, with the benefit of experienced browser developers santity-checking the work as we go.