move common blur types into central header

BUG=skia:
R=scroggo@google.com, djsollen@google.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/253833002

git-svn-id: http://skia.googlecode.com/svn/trunk@14411 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/samplecode/SampleXfermodesBlur.cpp b/samplecode/SampleXfermodesBlur.cpp
index de75d05..620de54 100644
--- a/samplecode/SampleXfermodesBlur.cpp
+++ b/samplecode/SampleXfermodesBlur.cpp
@@ -46,7 +46,7 @@
     void draw_mode(SkCanvas* canvas, SkXfermode* mode, int alpha,
                    SkScalar x, SkScalar y) {
         SkPaint p;
-        SkMaskFilter* mf = SkBlurMaskFilter::Create(SkBlurMaskFilter::kNormal_BlurStyle,
+        SkMaskFilter* mf = SkBlurMaskFilter::Create(kNormal_SkBlurStyle,
                                        SkBlurMask::ConvertRadiusToSigma(SkIntToScalar(5)),
                                        SkBlurMaskFilter::kNone_BlurFlag);
         p.setMaskFilter(mf)->unref();