Since Microsoft's position is now "implement Chrome with Bing as the search default", I am pretty sure most, if not all, web standards Google proposes will be enthusiastically supported by Microsoft, as they'll support them regardless.
Microsoft's claim is that they'll be more like Google and Apple working on WebKit. They disagreed a fair amount, and didn't always enable each other's features just because the other browser enabled them.
It will be interesting to see if Microsoft ever diverges from the web platform functionality exposed by Chrome. My prediction is that either they never do it, or they eventually do it and are forced to fork. Chromium is not as open to variation in the main tree as WebKit was when Google showed up.
