Reinstate early out from antialiased path rendering if we anticipate overflow

If the intersection of the bounds of the path & the bounds of the clip have any coordinates >= 8192, we'll overflow & render incorrectly if we go through the antialiased code, so fall back to SkScan::FillPath().

Works around http://code.google.com/p/chromium/issues/detail?id=121405

[TomH, 2012-04-09 20:13:25]

Looks fine in test case (just turns antialiasing off once we pass x=8192);
currently running layout tests to verify.

[TomH, 2012-04-10 14:09:28]

This breaks 4 layout tests:
  fast/box-shadow/*

Also, todos from verbal review:
 - write helper function for rects
 - redocument bit or tricks
 - add asserts for 8191, 8192, 32767, 32768

[TomH, 2012-04-11 21:03:03]

Should be good to go now.

If we have an inverse path fill, we may need to fill the entire clip, so we have
to abort AA and fail over to non-AA if the clip is too big.

If it isn't an inverse path fill, we can do AA so long as the intersection of
clip bounds and path bounds fits inside the limits of AA.

[reed1, 2012-04-12 12:54:02]

doesn't pathClippedOut mean nothing will draw?

[TomH, 2012-04-12 13:21:42]

I sure think so - if you think so too, I'll try throwing away the draw there. :)

[TomH, 2012-04-12 14:14:53]

Early exit passes both gms and LayoutTests.

[reed1, 2012-04-12 14:17:05]

sweet -- lgtm

[TomH, 2012-04-12 14:24:23]

Committed as r3658.