Remove unused SK_SUPPORT_LEGACY_ROUND_MIPMAP_LEVEL_CHOICE guard

src/core/SkMipMap.cpp

Index: src/core/SkMipMap.cpp
diff --git a/src/core/SkMipMap.cpp b/src/core/SkMipMap.cpp
index 8f38ede7f3d72a8a770f6421433613888b90763c..4a548b8562c2b8ed0f87939466306939d30e6129 100644
--- a/src/core/SkMipMap.cpp
+++ b/src/core/SkMipMap.cpp
@@ -334,12 +334,8 @@ bool SkMipMap::extractLevel(SkScalar scale, Level* levelPtr) const {
         return false;
     }
     SkASSERT(L >= 0);
-#ifdef SK_SUPPORT_LEGACY_ROUND_MIPMAP_LEVEL_CHOICE
-    int level = SkScalarRoundToInt(L);
-#else
 //    int rndLevel = SkScalarRoundToInt(L);
     int level = SkScalarFloorToInt(L);
-#endif
 //    SkDebugf("mipmap scale=%g L=%g level=%d rndLevel=%d\n", scale, L, level, rndLevel);
 
     SkASSERT(level >= 0);