Make some foo.h headers usable without foo-inl.h header.

src/types.h

 // Copyright 2014 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_TYPES_H_
 #define V8_TYPES_H_
 
 #include "src/conversions.h"
-#include "src/factory.h"
 #include "src/handles.h"
+#include "src/objects.h"
 #include "src/ostreams.h"
 
 namespace v8 {
 namespace internal {
 
 // SUMMARY
 //
 // A simple type system for compiler-internal use. It is based entirely on
 // union types, and all subtyping hence amounts to set inclusion. Besides the
 // obvious primitive types and some predefined unions, the type language also
@@ skipping 975 matching lines @@
   struct Range {
     void* tag;
     int bitset;
     double limits[2];
   };
   typedef i::Zone Region;
   template<class T> struct Handle { typedef T* type; };
 
   static const int kRangeStructTag = 0x1000;
 
-  template<class T> static inline T* null_handle();
+  template<class T> static inline T* null_handle() { return nullptr; }
   template<class T> static inline T* handle(T* type);
   template<class T> static inline T* cast(Type* type);
 
   static inline bool is_bitset(Type* type);
   static inline bool is_class(Type* type);
   static inline bool is_struct(Type* type, int tag);
   static inline bool is_range(Type* type);
 
   static inline Type::bitset as_bitset(Type* type);
   static inline i::Handle<i::Map> as_class(Type* type);
@@ skipping 34 matching lines @@
 struct HeapTypeConfig {
   typedef TypeImpl<HeapTypeConfig> Type;
   typedef i::Object Base;
   typedef i::FixedArray Struct;
   typedef i::FixedArray Range;
   typedef i::Isolate Region;
   template<class T> struct Handle { typedef i::Handle<T> type; };
 
   static const int kRangeStructTag = 0xffff;
 
-  template<class T> static inline i::Handle<T> null_handle();
+  template<class T> static inline i::Handle<T> null_handle() {
+    return i::Handle<T>();
+  }
   template<class T> static inline i::Handle<T> handle(T* type);
   template<class T> static inline i::Handle<T> cast(i::Handle<Type> type);
 
   static inline bool is_bitset(Type* type);
   static inline bool is_class(Type* type);
   static inline bool is_struct(Type* type, int tag);
   static inline bool is_range(Type* type);
 
   static inline Type::bitset as_bitset(Type* type);
   static inline i::Handle<i::Map> as_class(Type* type);
@@ skipping 91 matching lines @@
   bool Narrows(BoundsImpl that) {
     return that.lower->Is(this->lower) && this->upper->Is(that.upper);
   }
 };
 
 typedef BoundsImpl<ZoneTypeConfig> Bounds;
 
 } }  // namespace v8::internal
 
 #endif  // V8_TYPES_H_