fix warnings around size_t/int

src/utils/SkMatrix22.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
+#ifndef SkMatrix22_DEFINED
+#define SkMatrix22_DEFINED
+
 #include "SkPoint.h"
 
 class SkMatrix;
 
 /** Find the Givens matrix G, which is the rotational matrix
  *  that rotates the vector h to the positive hoizontal axis.
  *  G * h = [hypot(h), 0]
  *
  *  This is equivalent to
  *
  *  SkScalar r = h.length();
  *  SkScalar r_inv = r ? SkScalarInvert(r) : 0;
  *  h.scale(r_inv);
  *  G->setSinCos(-h.fY, h.fX);
  *
  *  but has better numerical stability by using (partial) hypot,
  *  and saves a multiply by not computing r.
  */
 void SkComputeGivensRotation(const SkVector& h, SkMatrix* G);
+
+#endif