Make SkSmallAllocator obey the RAII invariants and be expandable

tests/Float16Test.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Test.h"
+
+#include <cmath>
+
 #include "SkAutoPixmapStorage.h"
 #include "SkColor.h"
 #include "SkHalf.h"
 #include "SkOpts.h"
 #include "SkPixmap.h"
 #include "SkPM4f.h"
 #include "SkRandom.h"
 
 static bool eq_within_half_float(float a, float b) {
     const float kTolerance = 1.0f / (1 << (8 + 10));
@@ skipping 74 matching lines @@
 
         uint16_t expected = SkFloatToHalf(f);
         if (!is_finite(expected)) {
             // _finite_ftz() only works for values that can be represented as a finite half float.
             continue;
         }
 
         uint16_t alternate = expected;
         if (is_denorm(expected)) {
             // _finite_ftz() may flush denorms to zero, and happens to keep the sign bit.
-            alternate = signbit(f) ? 0x8000 : 0x0000;
+            alternate = std::signbit(f) ? 0x8000 : 0x0000;

[bungeman-skia, 2016/11/09 19:30:56]

This change seems unrelated?

[herb_g, 2016/11/09 20:20:05]

Removed

         }
 
         uint16_t actual = SkFloatToHalf_finite_ftz(Sk4f{f})[0];
         // _finite_ftz() may truncate instead of rounding, so it may be one too small.
         REPORTER_ASSERT(r, actual == expected  || actual == expected  - 1 ||
                            actual == alternate || actual == alternate - 1);
     }
 }