Call enterfullscreen() when creating the WebMediaPlayer for fullscreen element

For the same HTMLMediaElement, the WebMediaPlayer can get recreated if src changes.
However, the fullscreen status of the media element will remain unchanged.
On android, we need to know whether the newly created WebMediaPlayer is fullscreen or not.
This is because we need to pass the surface view to the new WebMediaPlayer.
This change calls the enterfullscreen() function to let the WebMediaPlayer to pass the surface.


New layout test will be added once this CL goes in, and the chromium side change is submitted

BUG=428209

Review URL: https://codereview.chromium.org/644153005

git-svn-id: svn://svn.chromium.org/blink/trunk@185064 bbb929c8-8fbe-4397-9dbb-9b2b20218538