Move platform abstraction to base library

src/v8checks.h

-// Copyright 2006-2008 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_V8CHECKS_H_
-#define V8_V8CHECKS_H_
-
-#include "src/checks.h"
-
-namespace v8 {
-  class Value;
-  template <class T> class Handle;
-
-namespace internal {
-  intptr_t HeapObjectTagMask();
-
-} }  // namespace v8::internal
-
-
-void CheckNonEqualsHelper(const char* file,
-                          int line,
-                          const char* unexpected_source,
-                          v8::Handle<v8::Value> unexpected,
-                          const char* value_source,
-                          v8::Handle<v8::Value> value);
-
-void CheckEqualsHelper(const char* file,
-                       int line,
-                       const char* expected_source,
-                       v8::Handle<v8::Value> expected,
-                       const char* value_source,
-                       v8::Handle<v8::Value> value);
-
-#define ASSERT_TAG_ALIGNED(address) \
-  ASSERT((reinterpret_cast<intptr_t>(address) & HeapObjectTagMask()) == 0)
-
-#define ASSERT_SIZE_TAG_ALIGNED(size) ASSERT((size & HeapObjectTagMask()) == 0)
-
-#endif  // V8_V8CHECKS_H_