Fix arrow functions requiring context without slots.

src/code-stubs.h

 // Copyright 2012 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_CODE_STUBS_H_
 #define V8_CODE_STUBS_H_
 
 #include "src/allocation.h"
 #include "src/assembler.h"
 #include "src/codegen.h"
@@ skipping 714 matching lines @@
   DEFINE_CALL_INTERFACE_DESCRIPTOR(FastNewClosure);
   DEFINE_HYDROGEN_CODE_STUB(FastNewClosure, HydrogenCodeStub);
 };
 
 
 class FastNewContextStub final : public HydrogenCodeStub {
  public:
   static const int kMaximumSlots = 64;
 
   FastNewContextStub(Isolate* isolate, int slots) : HydrogenCodeStub(isolate) {
-    DCHECK(slots > 0 && slots <= kMaximumSlots);
+    DCHECK(slots >= 0 && slots <= kMaximumSlots);
     set_sub_minor_key(SlotsBits::encode(slots));
   }
 
   int slots() const { return SlotsBits::decode(sub_minor_key()); }
 
   // Parameters accessed via CodeStubGraphBuilder::GetParameter()
   static const int kFunction = 0;
 
  private:
   class SlotsBits : public BitField<int, 0, 8> {};
@@ skipping 2220 matching lines @@
 
 #undef DEFINE_CALL_INTERFACE_DESCRIPTOR
 #undef DEFINE_PLATFORM_CODE_STUB
 #undef DEFINE_HANDLER_CODE_STUB
 #undef DEFINE_HYDROGEN_CODE_STUB
 #undef DEFINE_CODE_STUB
 #undef DEFINE_CODE_STUB_BASE
 } }  // namespace v8::internal
 
 #endif  // V8_CODE_STUBS_H_