Add #include first in Sk4x_* files

src/core/Sk4x_neon.h

 // It is important _not_ to put header guards here.
 // This file will be intentionally included three times.
 
+#include "SkTypes.h"  // Keep this before any #ifdef for skbug.com/3362
+
 #if defined(SK4X_PREAMBLE)
     #include <arm_neon.h>
 
     // Template metaprogramming to map scalar types to vector types.
     template <typename T> struct SkScalarToSIMD;
     template <> struct SkScalarToSIMD<float>   { typedef float32x4_t  Type; };
     template <> struct SkScalarToSIMD<int32_t> { typedef int32x4_t Type; };
 
 #elif defined(SK4X_PRIVATE)
     Sk4x(float32x4_t);
@@ skipping 197 matching lines @@
 }
 M(Sk4i) ZWCD(const Sk4i& xyzw, const Sk4i& abcd) {
     int32x4x2_t xayb_zcwd = vzipq_s32(xyzw.fVec, abcd.fVec);
     int32x4x2_t axby_czdw = vzipq_s32(abcd.fVec, xyzw.fVec);
     return vuzpq_s32(xayb_zcwd.val[1], axby_czdw.val[1]).val[0];
 }
 
 #undef M
 
 #endif