Push sigma-based blur interface into our GMs/benches/tests/samplecode

samplecode/SampleStrokePath.cpp

Index: samplecode/SampleStrokePath.cpp
===================================================================
--- samplecode/SampleStrokePath.cpp	(revision 11004)
+++ samplecode/SampleStrokePath.cpp	(working copy)
@@ -168,14 +168,14 @@
             };
             for (int x = 0; x < 5; x++) {
                 SkMaskFilter* mf;
-                SkScalar radius = 4;
+                SkScalar sigma = SkFloatToScalar(2.8094f);
                 for (int y = 0; y < 10; y++) {
                     if (x) {
-                        mf = SkBlurMaskFilter::Create(radius, gStyle[x - 1]);
+                        mf = SkBlurMaskFilter::Create(gStyle[x - 1], sigma);
                         paint.setMaskFilter(mf)->unref();
                     }
                     canvas->drawText("Title Bar", 9, x*SkIntToScalar(100), y*SkIntToScalar(30), paint);
-                    radius *= 0.75f;
+                    sigma *= 0.75f;
                 }
 
             }