add COMPILE_ASSERT(sizeof(Foo) == 32) for classes we're trying to keep small
Now that we have these magical COMPILE_ASSERTs we should use them to make sure we don't accidentally inflate core classes with changes.
Simon or Alan: Is there anything actionable here? Eric didn't list specific classes when he filed this, so I'm not sure which ones he was thinking of.
I don't think this bug itself is actionable.
But, note that we are already doing this thing for some of super important classes (in particular in JSC).