4190 [camera_web] Add buildPreview implementation (cla: yes, waiting for tree to go green, p: camera, platform-web)

4191 [camera_platform_interface] Expand camera platform interface to support pausing the camera preview. (cla: yes, waiting for tree to go green, p: camera)

4196 [camera_web] Add takePicture implementation (cla: yes, waiting for tree to go green, p: camera, platform-web)

4197 [camera] Fix camera preview not always rebuilding on orientation change (cla: yes, waiting for tree to go green, p: camera)

4203 [camera_web] Add dispose implementation (cla: yes, waiting for tree to go green, p: camera, platform-web)

4207 [camera_web] Add camera errors handling (cla: yes, waiting for tree to go green, p: camera, platform-web)