Have HTMLElements / SVGElements constructors take a Document reference in argument

Have HTMLElements / SVGElements constructors take a Document reference in argument
instead of a pointer as it can never be NULL. Most callers already have a document
reference so this change avoids having to convert them into pointers.

BUG=281400
R=haraken@chromium.org, tkent@chromium.org

Review URL: https://codereview.chromium.org/23886003

git-svn-id: svn://svn.chromium.org/blink/trunk@157125 bbb929c8-8fbe-4397-9dbb-9b2b20218538