Decouple CpuFeatures from serializer state.

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 9d421ef6c11c10d4f76c386816615b938f44d7f2..d844d92599640fe6940318c56f379213e23ae98a 100644
--- a/src/x64/assembler-x64.h
+++ b/src/x64/assembler-x64.h
@@ -437,73 +437,6 @@ class Operand BASE_EMBEDDED {
 };
 
 
-// CpuFeatures keeps track of which features are supported by the target CPU.
-// Supported features must be enabled by a CpuFeatureScope before use.
-// Example:
-//   if (assembler->IsSupported(SSE3)) {
-//     CpuFeatureScope fscope(assembler, SSE3);
-//     // Generate SSE3 floating point code.
-//   } else {
-//     // Generate standard SSE2 floating point code.
-//   }
-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(bool serializer_enabled);
-
-  // Check whether a feature is supported by the target CPU.
-  static bool IsSupported(CpuFeature f) {
-    if (Check(f, cross_compile_)) return true;
-    ASSERT(initialized_);
-    if (f == SSE3 && !FLAG_enable_sse3) return false;
-    if (f == SSE4_1 && !FLAG_enable_sse4_1) return false;
-    if (f == SAHF && !FLAG_enable_sahf) return false;
-    return Check(f, supported_);
-  }
-
-  static bool IsSafeForSnapshot(Isolate* isolate, CpuFeature f) {
-    return Check(f, cross_compile_) ||
-           (IsSupported(f) &&
-            !(Serializer::enabled(isolate) &&
-              Check(f, found_by_runtime_probing_only_)));
-  }
-
-  static bool VerifyCrossCompiling() {
-    return cross_compile_ == 0;
-  }
-
-  static bool VerifyCrossCompiling(CpuFeature f) {
-    uint64_t mask = flag2set(f);
-    return cross_compile_ == 0 ||
-           (cross_compile_ & mask) == mask;
-  }
-
-  static bool SupportsCrankshaft() { return true; }
-
- private:
-  static bool Check(CpuFeature f, uint64_t set) {
-    return (set & flag2set(f)) != 0;
-  }
-
-  static uint64_t flag2set(CpuFeature f) {
-    return static_cast<uint64_t>(1) << f;
-  }
-
-#ifdef DEBUG
-  static bool initialized_;
-#endif
-  static uint64_t supported_;
-  static uint64_t found_by_runtime_probing_only_;
-
-  static uint64_t cross_compile_;
-
-  friend class ExternalReference;
-  friend class PlatformFeatureScope;
-  DISALLOW_COPY_AND_ASSIGN(CpuFeatures);
-};
-
-
 #define ASSEMBLER_INSTRUCTION_LIST(V)   \
   V(add)                                \
   V(and)                                \