Simplified CPU/CpuFeatures a bit.

src/arm64/cpu-arm64.h

Index: src/arm64/cpu-arm64.h
diff --git a/src/arm64/cpu-arm64.h b/src/arm64/cpu-arm64.h
index ddec72d8f68f571c59fa7e66152558a8bc213a64..009cead82a08ebd207f58517fa538efbc25745d0 100644
--- a/src/arm64/cpu-arm64.h
+++ b/src/arm64/cpu-arm64.h
@@ -42,7 +42,7 @@ class CpuFeatures : public AllStatic {
  public:
   // Detect features of the target CPU. Set safe defaults if the serializer
   // is enabled (snapshots must be portable).
-  static void Probe();
+  static void Probe(bool serializer_enabled);
 
   // Check whether a feature is supported by the target CPU.
   static bool IsSupported(CpuFeature f) {
@@ -81,6 +81,8 @@ class CpuFeatures : public AllStatic {
     return true;
   }
 
+  static bool SupportsCrankshaft() { return true; }
+
  private:
   // Return the content of the cache type register.
   static uint32_t GetCacheType();