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/gm/drawbitmaprect.cpp b/gm/drawbitmaprect.cpp
index 3cc9026..bc7e035 100644
--- a/gm/drawbitmaprect.cpp
+++ b/gm/drawbitmaprect.cpp
@@ -163,7 +163,7 @@
 
             srcRect.setXYWH(1, 1, 3, 3);
             SkMaskFilter* mf = SkBlurMaskFilter::Create(
-                SkBlurMaskFilter::kNormal_BlurStyle,
+                kNormal_SkBlurStyle,
                 SkBlurMask::ConvertRadiusToSigma(SkIntToScalar(5)),
                 SkBlurMaskFilter::kHighQuality_BlurFlag |
                 SkBlurMaskFilter::kIgnoreTransform_BlurFlag);