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/bench/BlurRoundRectBench.cpp b/bench/BlurRoundRectBench.cpp
index a3d0ba9..43391bf 100644
--- a/bench/BlurRoundRectBench.cpp
+++ b/bench/BlurRoundRectBench.cpp
@@ -50,7 +50,7 @@
             info.fPostTranslate = false;
             SkPaint* paint = looperBuilder.addLayerOnTop(info);
             SkMaskFilter* maskFilter = SkBlurMaskFilter::Create(
-                    SkBlurMaskFilter::kNormal_BlurStyle,
+                    kNormal_SkBlurStyle,
                     SkBlurMask::ConvertRadiusToSigma(SK_ScalarHalf),
                     SkBlurMaskFilter::kHighQuality_BlurFlag);
             paint->setMaskFilter(maskFilter)->unref();