For present purposes, § 151(a) must be read in conjunction with § 212(a).  In our view, one must look primarily to § 212(a), and not to § 151(a), for the validity of the P & W voting restrictions.  In the final analysis, these restrictions are limitations upon the voting rights of the stockholder, not variations in the voting powers of the stock per se.  The voting power of the stock in the hands of a large stockholder is not differentiated from all others in its class; it is the personal right of the stockholder to exercise that power that is altered by the size of his holding.

378 A.2d at 123.  
No California court has adopted Providence & Worcester in a reported decision.  To do so, it would have to get past the fact that Section 400(a) refers to "voting rights" rather than "voting power" (as in Section 151(a)).