Add the c++ code part of bindings2/

sky/engine/bindings2/exception_state_placeholder.h

Index: sky/engine/bindings2/exception_state_placeholder.h
diff --git a/sky/engine/bindings2/exception_state_placeholder.h b/sky/engine/bindings2/exception_state_placeholder.h
new file mode 100644
index 0000000000000000000000000000000000000000..7983f832a1826f2b08f2f918aac107eda5c692ef
--- /dev/null
+++ b/sky/engine/bindings2/exception_state_placeholder.h
@@ -0,0 +1,39 @@
+// Copyright 2014 The Chromium 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 SKY_ENGINE_BINDINGS2_EXCEPTION_STATE_PLACEHOLDER_H_
+#define SKY_ENGINE_BINDINGS2_EXCEPTION_STATE_PLACEHOLDER_H_
+
+#include "sky/engine/bindings2/exception_state.h"
+#include "sky/engine/wtf/Assertions.h"
+
+namespace blink {
+
+class IgnorableExceptionState final : public ExceptionState {
+ public:
+  ExceptionState& ReturnThis() { return *this; }
+};
+
+#define IGNORE_EXCEPTION (::blink::IgnorableExceptionState().ReturnThis())
+
+#if ENABLE(ASSERT)
+
+class NoExceptionStateAssertionChecker final : public ExceptionState {
+ public:
+  NoExceptionStateAssertionChecker(const char* file, int line);
+  ExceptionState& ReturnThis() { return *this; }
+};
+
+#define ASSERT_NO_EXCEPTION \
+  (::blink::NoExceptionStateAssertionChecker(__FILE__, __LINE__).ReturnThis())
+
+#else
+
+#define ASSERT_NO_EXCEPTION (::blink::IgnorableExceptionState().ReturnThis())
+
+#endif
+
+}  // namespace blink
+
+#endif  // SKY_ENGINE_BINDINGS2_EXCEPTION_STATE_PLACEHOLDER_H_