Use ARMv8 CRC32 instructions for SkOpts::hash().

src/core/SkOpts.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCpu.h"
 #include "SkHalf.h"
 #include "SkOnce.h"
@@ skipping 63 matching lines @@
 
     DEFINE_DEFAULT(hash_fn);
 #undef DEFINE_DEFAULT
 
     // Each Init_foo() is defined in src/opts/SkOpts_foo.cpp.
     void Init_ssse3();
     void Init_sse41();
     void Init_sse42();
     void Init_avx();
     void Init_avx2() {}
+    void Init_crc32();
 
     static void init() {
-    #if defined(SK_CPU_X86) && !defined(SK_BUILD_NO_OPTS)
+#if !defined(SK_BUILD_NO_OPTS)
+    #if defined(SK_CPU_X86)
         if (SkCpu::Supports(SkCpu::SSSE3)) { Init_ssse3(); }
         if (SkCpu::Supports(SkCpu::SSE41)) { Init_sse41(); }
         if (SkCpu::Supports(SkCpu::SSE42)) { Init_sse42(); }
         if (SkCpu::Supports(SkCpu::AVX  )) { Init_avx();   }
         if (SkCpu::Supports(SkCpu::AVX2 )) { Init_avx2();  }
+
+    #elif defined(SK_CPU_ARM64)
+        if (SkCpu::Supports(SkCpu::CRC32)) { Init_crc32(); }
+
     #endif
+#endif
     }
 
     void Init() {
         static SkOnce once;
         once(init);
     }
 }  // namespace SkOpts