[api] Clean up scopes and precheck instantiations cache

src/isolate-inl.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_ISOLATE_INL_H_
 #define V8_ISOLATE_INL_H_
 
 #include "src/isolate.h"
 #include "src/objects-inl.h"
 
@@ skipping 82 matching lines @@
 
 Isolate::ExceptionScope::ExceptionScope(Isolate* isolate)
     : isolate_(isolate),
       pending_exception_(isolate_->pending_exception(), isolate_) {}
 
 
 Isolate::ExceptionScope::~ExceptionScope() {
   isolate_->set_pending_exception(*pending_exception_);
 }
 
+SaveContext::SaveContext(Isolate* isolate)
+    : isolate_(isolate), prev_(isolate->save_context()) {
+  if (isolate->context() != NULL) {
+    context_ = Handle<Context>(isolate->context());
+  }
+  isolate->set_save_context(this);
+  c_entry_fp_ = isolate->c_entry_fp(isolate->thread_local_top());
+}
+
+SaveContext::~SaveContext() {
+  isolate_->set_context(context_.is_null() ? NULL : *context_);
+  isolate_->set_save_context(prev_);
+}
+
 #define NATIVE_CONTEXT_FIELD_ACCESSOR(index, type, name)     \
   Handle<type> Isolate::name() {                             \
     return Handle<type>(raw_native_context()->name(), this); \
   }                                                          \
   bool Isolate::is_##name(type* value) {                     \
     return raw_native_context()->is_##name(value);           \
   }
 NATIVE_CONTEXT_FIELDS(NATIVE_CONTEXT_FIELD_ACCESSOR)
 #undef NATIVE_CONTEXT_FIELD_ACCESSOR
 
@@ skipping 17 matching lines @@
 
 bool Isolate::IsHasInstanceLookupChainIntact() {
   PropertyCell* has_instance_cell = heap()->has_instance_protector();
   return has_instance_cell->value() == Smi::FromInt(kArrayProtectorValid);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ISOLATE_INL_H_