remove SK_SUPPORT_LEGACY_DIVBITS_UB -- chrome no longer defines this

include/private/SkFixed.h

Index: include/private/SkFixed.h
diff --git a/include/private/SkFixed.h b/include/private/SkFixed.h
index c90d5e9ffd093e98a7335fd210be962a2436ac3e..dade2399d13f458e1f0ba816ef29dbf734a4e8fb 100644
--- a/include/private/SkFixed.h
+++ b/include/private/SkFixed.h
@@ -98,14 +98,9 @@ static inline SkFixed SkDoublePinToFixed(double x) {
 #define SkFixedAbs(x)       SkAbs32(x)
 #define SkFixedAve(a, b)    (((a) + (b)) >> 1)
 
-// Blink layout tests are baselined to Clang optimizing through undefined behavior in SkDivBits.
-#if defined(SK_SUPPORT_LEGACY_DIVBITS_UB)
-    #define SkFixedDiv(numer, denom) SkDivBits(numer, denom, 16)
-#else
-    // The divide may exceed 32 bits. Clamp to a signed 32 bit result.
-    #define SkFixedDiv(numer, denom) \
-        SkToS32(SkTPin<int64_t>((SkLeftShift((int64_t)numer, 16) / denom), SK_MinS32, SK_MaxS32))
-#endif
+// The divide may exceed 32 bits. Clamp to a signed 32 bit result.
+#define SkFixedDiv(numer, denom) \
+    SkToS32(SkTPin<int64_t>((SkLeftShift((int64_t)numer, 16) / denom), SK_MinS32, SK_MaxS32))
 
 //////////////////////////////////////////////////////////////////////////////////////////////////////
 // Now look for ASM overrides for our portable versions (should consider putting this in its own file)