[bindings] Introduce ScriptValue.to<T> to convert to native values.

Source/bindings/modules/v8/V8BindingForModules.h

 // Copyright (c) 2015 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 V8BindingForModules_h
 #define V8BindingForModules_h
 
 #include "bindings/core/v8/V8Binding.h"
 #include "modules/webdatabase/sqlite/SQLValue.h"
 
 namespace blink {
 
 class IDBAny;
 class IDBKey;
 class IDBKeyPath;
 class IDBKeyRange;
 class SerializedScriptValue;
 class SharedBuffer;
 class WebBlobInfo;
 
 // Exposed for unit testing:
 bool injectV8KeyIntoV8Value(v8::Isolate*, v8::Local<v8::Value> key, v8::Local<v8::Value>, const IDBKeyPath&);
 
 // For use by Source/modules/indexeddb:
 IDBKey* createIDBKeyFromScriptValueAndKeyPath(v8::Isolate*, const ScriptValue&, const IDBKeyPath&);
 bool canInjectIDBKeyIntoScriptValue(v8::Isolate*, const ScriptValue&, const IDBKeyPath&);
-IDBKey* scriptValueToIDBKey(v8::Isolate*, const ScriptValue&);
-IDBKeyRange* scriptValueToIDBKeyRange(v8::Isolate*, const ScriptValue&);
 ScriptValue deserializeScriptValue(ScriptState*, SerializedScriptValue*, const Vector<blink::WebBlobInfo>*);
 
 #if ENABLE(ASSERT)
 void assertPrimaryKeyValidOrInjectable(ScriptState*, PassRefPtr<SharedBuffer>, const Vector<blink::WebBlobInfo>*, IDBKey*, const IDBKeyPath&);
 #endif
 
 template <>
 struct NativeValueTraits<SQLValue> {
     static SQLValue nativeValue(const v8::Local<v8::Value>&, v8::Isolate*, ExceptionState&);
 };
 
 template <>
 struct NativeValueTraits<IDBKey*> {
     static IDBKey* nativeValue(const v8::Local<v8::Value>&, v8::Isolate*, ExceptionState&);
 };
 
 template <>
 struct NativeValueTraits<IDBKeyRange*> {
     static IDBKeyRange* nativeValue(const v8::Local<v8::Value>&, v8::Isolate*, ExceptionState&);
 };
 
 } // namespace blink
 
 #endif // V8BindingForModules_h