Remove ENABLE(MEDIA_STREAM) from Navigator.h

Remove ENABLE(MEDIA_STREAM) from Navigator.h
https://bugs.webkit.org/show_bug.cgi?id=78467

Reviewed by Kentaro Hara.

Navigator.webkitGetUser media doesn't really have anything to do with
Navigator.cpp.  This patch moves it into the mediastream directory and
removes the ENABLE(MEDIA_STREAM) ifdefs in Navigator.h and
Navigator.cpp.

* GNUmakefile.list.am:
* WebCore.gypi:
* mediastream/NavigatorMediaStream.cpp: Added.
(WebCore):
(WebCore::NavigatorMediaStream::NavigatorMediaStream):
(WebCore::NavigatorMediaStream::~NavigatorMediaStream):
(WebCore::NavigatorMediaStream::webkitGetUserMedia):
* mediastream/NavigatorMediaStream.h: Added.
(WebCore):
(NavigatorMediaStream):
* mediastream/NavigatorMediaStream.idl: Added.
* page/Navigator.cpp:
(WebCore):
* page/Navigator.h:
(WebCore):
(Navigator):
* page/Navigator.idl:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@107541 268f45cc-cd09-0410-ab3c-d52691b4dbfc