UCLA Law Professor Stephen Bainbridge recently answered the question of whether shareholders may remove a corporation's chief executive officer and chairman of the board from a Delaware perspective.  Like Delaware, California provides a statutory answer:

Except as otherwise provided by the articles or bylaws, officers shall be chosen by the board and serve at the pleasure of the board, subject to the rights, if any, of an officer under any contract of employment. Any officer may resign at any time upon written notice to the corporation without prejudice to the rights, if any, of the corporation under any contract to which the officer is a party.

Cal. Corp. Code § 312(b).  In my experience, it is unusual for the articles of incorporation to address the removal of corporate officers.  To the extent that bylaws address removal, they typically parrot the statute.  

Professor Bainbridge's post does not address whether the position of chairman of the board is an officer position, a question that I discussed 11 years ago in this post.  As I then observed, the classification of the chairman position can have important implications, including exculpation and the application of the business judgment rule.