PTAL
Otherwise, LGTM. http://codereview.appspot.com/5972065/diff/1/gm/shadows.cpp File gm/shadows.cpp (right): http://codereview.appspot.com/5972065/diff/1/gm/shadows.cpp#newcode88 gm/shadows.cpp:88: { SK_ColorBLUE, SkFloatToScalar(0.9f)}, Maybe we should make this be 0 (hairline by caller's choice rather than taking the stroke-width < 1 optimization path). That way it stays hairline when zoomed (in SampleApp) and we won't lose the coverage if the hairline optimization changes.
Fixed with r3612