Add isRect variant that returns path closure and direction.

Add path test to verify that when isRect() returns false,
output parameters are unchanged.
Review URL: https://codereview.appspot.com/6855074

git-svn-id: http://skia.googlecode.com/svn/trunk@6524 2bbb7eff-a529-9590-31e7-b0007b416f81
3 files changed