Simplified CPU/CpuFeatures a bit.

src/x64/assembler-x64.h

Index: src/x64/assembler-x64.h
diff --git a/src/x64/assembler-x64.h b/src/x64/assembler-x64.h
index 43475d11e13464b449d1eadf8caf29fe9b6aca5f..702be58c2933b77cc6f0e37c07c2d032f5427245 100644
--- a/src/x64/assembler-x64.h
+++ b/src/x64/assembler-x64.h
@@ -450,7 +450,7 @@ 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) {
@@ -484,6 +484,8 @@ class CpuFeatures : public AllStatic {
            (cross_compile_ & mask) == mask;
   }
 
+  static bool SupportsCrankshaft() { return true; }
+
  private:
   static bool Check(CpuFeature f, uint64_t set) {
     return (set & flag2set(f)) != 0;