Collaboration = partnership with stakeholders in decision-making, including them in our decision-making. This is the result of engagement, which is the result of trust & legitimacy - shared values - enterprise level strategy - culture- input. Thus, if CC works towards stakeholder collaboration, it will automatically lead to including stakeholders in comm strategy development.
Corporate governance = governing org in meeting TBL responsibilities. If one looks at it from a comm perspective, to meet these responsibilities, one must meet the needs & expectations of stakeholders to best interest of org. This only happens if there is collaboration... etc. Remember that corp governance also provides guidance for CC strategy.