Remove redundant use of inline keyword in FloatingObject methods.

inline is the default for member functions defined inside their class.
http://stackoverflow.com/questions/10103161/inline-keyword-vs-header-definition

BUG=271774
R=jyasskin@chromium.org

Review URL: https://codereview.chromium.org/22854008

git-svn-id: svn://svn.chromium.org/blink/trunk@155966 bbb929c8-8fbe-4397-9dbb-9b2b20218538