Make FlushICache part of Assembler(Base) and take Isolate as parameter.

src/x64/codegen-x64.cc

Index: src/x64/codegen-x64.cc
diff --git a/src/x64/codegen-x64.cc b/src/x64/codegen-x64.cc
index ceb0dd4345e1c1cfbbe6be80dc3519fc8b6aa478..87695f4c825ce9962231c010c6e5d284df165c09 100644
--- a/src/x64/codegen-x64.cc
+++ b/src/x64/codegen-x64.cc
@@ -58,7 +58,7 @@ UnaryMathFunction CreateExpFunction() {
   masm.GetCode(&desc);
   DCHECK(!RelocInfo::RequiresRelocation(desc));
 
-  CpuFeatures::FlushICache(buffer, actual_size);
+  Assembler::FlushICacheWithoutIsolate(buffer, actual_size);
   base::OS::ProtectCode(buffer, actual_size);
   return FUNCTION_CAST<UnaryMathFunction>(buffer);
 }
@@ -81,7 +81,7 @@ UnaryMathFunction CreateSqrtFunction() {
   masm.GetCode(&desc);
   DCHECK(!RelocInfo::RequiresRelocation(desc));
 
-  CpuFeatures::FlushICache(buffer, actual_size);
+  Assembler::FlushICacheWithoutIsolate(buffer, actual_size);
   base::OS::ProtectCode(buffer, actual_size);
   return FUNCTION_CAST<UnaryMathFunction>(buffer);
 }
@@ -692,7 +692,7 @@ void Code::PatchPlatformCodeAge(Isolate* isolate,
   uint32_t young_length = isolate->code_aging_helper()->young_sequence_length();
   if (age == kNoAgeCodeAge) {
     isolate->code_aging_helper()->CopyYoungSequenceTo(sequence);
-    CpuFeatures::FlushICache(sequence, young_length);
+    Assembler::FlushICacheWithoutIsolate(sequence, young_length);
   } else {
     Code* stub = GetCodeAgeStub(isolate, age, parity);
     CodePatcher patcher(sequence, young_length);