Silence narrowing warning with XRectangle

XRectangle is defined as such in <X11/Xlib.h>:

typedef struct {
    short x, y;
    unsigned short width, height;
} XRectangle;

BUG=none

Review URL: https://codereview.chromium.org/25647004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227083 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed