Clean up hyper-local SkCpu feature test experiment.

src/core/SkCpu.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.
  */
 
-#define SkCpu_IMPL
 #include "SkCpu.h"
 #include "SkOnce.h"
 
 #if defined(SK_CPU_X86)
     #if defined(SK_BUILD_FOR_WIN32)
         #include <intrin.h>
         static void cpuid (uint32_t abcd[4]) { __cpuid  ((int*)abcd, 1);    }
         static void cpuid7(uint32_t abcd[4]) { __cpuidex((int*)abcd, 7, 0); }
         static uint64_t xgetbv(uint32_t xcr) { return _xgetbv(xcr); }
     #else
@@ skipping 53 matching lines @@
         return features;
     }
 
 #else
     static uint32_t read_cpu_features() {
         return 0;
     }
 
 #endif
 
-#if defined(_MSC_VER)
-    const uint32_t SkCpu::gCachedFeatures = read_cpu_features();
+uint32_t SkCpu::gCachedFeatures = 0;
 
-    void SkCpu::CacheRuntimeFeatures() {}
-
-#else
-    uint32_t SkCpu::gCachedFeatures = 0;
-
-    void SkCpu::CacheRuntimeFeatures() {
-        static SkOnce once;
-        once([] { gCachedFeatures = read_cpu_features(); });
-    }
-
-#endif
+void SkCpu::CacheRuntimeFeatures() {
+    static SkOnce once;
+    once([] { gCachedFeatures = read_cpu_features(); });
+}