This CL makes the ctor public and externally usable by changing the camera id argument from an int to a String. The main purpose with this change is to get rid of the CameraEnumerationAndroid.setEnumerator() hack. If an external app wants to have a custom format enumeration, they can just override getSupportedFormats() instead. BUG=webrtc:5519 Review-Url: https://codereview.webrtc.org/2012193003 Cr-Commit-Position: refs/heads/master@{#12945}