Remove implicit flooring Scale() method from Point and Size.

When scaling an integer point or size, return a floating point
result. Implicitly flooring hides design problems and bugs. Add
conversion functions to floor or ceil a SizeF or PointF
into an integer format again.

All existing behaviour has been preserved by replacing uses of
foo.Scale() with ToFlooredFoo(foo.Scale()).

R=sky
BUG=147395


Review URL: https://chromiumcodereview.appspot.com/11081007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@160970 0039d316-1c4b-4281-b951-d872f2087c98
38 files changed