1. A method for mediating a communication request between a native application and a browser-based application on a computing device, the method comprising: receiving, using at least one processor, the communication request from the browser-based application, wherein the request specifies a native application messaging host; determining, using the at least one processor and based on a manifest file associated with the native application messaging host and distributed with the native application, whether the browser-based application is authorized to communicate with the native application by identifying whether the browser-based application is identified in the manifest file and determining that the native application messaging host specified in the communication request is associated with the manifest file; and forwarding, using the at least one processor, the communication request to the native application messaging host when it is determined that the browser-based application is authorized, and in response to determining that no manifest file is associated with the native application messaging host, sending a response to the browser-based application indicating the communication request was in error.