gl/eagl: internal view resize fixes for glimagesink

!681 (merged) introduced an internal_view and some resize handling changes with it. Unfortunately this appears to have resulted in the rendered video not being resized to match the native window handle size changes.

For example if initially it is created in the bottom center of the screen and then resized to be on the whole screen, it would show a single fullscreen frame (sometimes) and then continue in the old smaller size in the bottom left corner. Additionally it was calling the resize function on each draw_cb in the smaller size, because of double vs int type issues (and I happened to end up with a width of 103.5 or similar), but then after resizing it, it never called it when needed with the new values.

This set of commits tries to remedy this.