Simplified CPU/CpuFeatures a bit.

src/ia32/assembler-ia32.h

Index: src/ia32/assembler-ia32.h
diff --git a/src/ia32/assembler-ia32.h b/src/ia32/assembler-ia32.h
index 2a8e454c41867891ff8f5eb08928d75ac2a5596c..30c13a382b6fa26743ffa128ee12fdaf798a7e0f 100644
--- a/src/ia32/assembler-ia32.h
+++ b/src/ia32/assembler-ia32.h
@@ -530,7 +530,7 @@ 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) {
@@ -564,6 +564,8 @@ class CpuFeatures : public AllStatic {
            (cross_compile_ & mask) == mask;
   }
 
+  static bool SupportsCrankshaft() { return IsSupported(SSE2); }
+
  private:
   static bool Check(CpuFeature f, uint64_t set) {
     return (set & flag2set(f)) != 0;