Revert "Remove support for MSVC"

sky/engine/bindings/core/v8/ScriptWrappable.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 30 matching lines @@
 /**
  * The base class of all wrappable objects.
  *
  * This class provides the internal pointer to be stored in the wrapper objects,
  * and its conversions from / to the DOM instances.
  *
  * Note that this class must not have vtbl (any virtual function) or any member
  * variable which increase the size of instances. Some of the classes sensitive
  * to the size inherit from this class. So this class must be zero size.
  */
+#if COMPILER(MSVC)
+// VC++ 2013 doesn't support EBCO (Empty Base Class Optimization). It causes
+// that not always pointers to an empty base class are aligned to 4 byte
+// alignment. For example,
+//
+//   class EmptyBase1 {};
+//   class EmptyBase2 {};
+//   class Derived : public EmptyBase1, public EmptyBase2 {};
+//   Derived d;
+//   // &d                           == 0x1000
+//   // static_cast<EmptyBase1*>(&d) == 0x1000
+//   // static_cast<EmptyBase2*>(&d) == 0x1001  // Not 4 byte alignment!
+//
+// This doesn't happen with other compilers which support EBCO. All the
+// addresses in the above example will be 0x1000 with EBCO supported.
+//
+// Since v8::Object::SetAlignedPointerInInternalField requires the pointers to
+// be aligned, we need a hack to specify at least 4 byte alignment to MSVC.
+__declspec(align(4))
+#endif
 class ScriptWrappableBase {
 public:
     template<typename T>
     T* toImpl()
     {
         // Check if T* is castable to ScriptWrappableBase*, which means T
         // doesn't have two or more ScriptWrappableBase as superclasses.
         // If T has two ScriptWrappableBase as superclasses, conversions
         // from T* to ScriptWrappableBase* are ambiguous.
         ASSERT(static_cast<ScriptWrappableBase*>(static_cast<T*>(this)));
@@ skipping 185 matching lines @@
     virtual const WrapperTypeInfo* wrapperTypeInfo() const override \
     { \
         return &s_wrapperTypeInfo; \
     } \
 private: \
     static const WrapperTypeInfo& s_wrapperTypeInfo
 
 } // namespace blink
 
 #endif // ScriptWrappable_h