Add initial support for [Exposed=xx] extended IDL attribute

Source/core/html/canvas/DataView.idl

 /*
  * 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
  *     documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 [
     Custom=Wrap,
     CustomConstructor(ArrayBuffer buffer, optional unsigned long byteOffset, optional unsigned long byteLength),
-    GlobalContext=Window&WorkerGlobalScope,
+    Exposed=Window&Worker,
     TypeChecking=Interface|Nullable,
 ] interface DataView : ArrayBufferView {
     // All these methods raise an exception if they would read or write beyond the end of the view.
 
     [RaisesException] byte getInt8(unsigned long byteOffset);
     [RaisesException] octet getUint8(unsigned long byteOffset);
 
     [RaisesException] short getInt16(unsigned long byteOffset, optional boolean littleEndian);
     [RaisesException] unsigned short getUint16(unsigned long byteOffset, optional boolean littleEndian);
     [RaisesException] long getInt32(unsigned long byteOffset, optional boolean littleEndian);
     [RaisesException] unsigned long getUint32(unsigned long byteOffset, optional boolean littleEndian);
 
     // Use custom code to handle NaN case for JSC.
     [RaisesException] float getFloat32(unsigned long byteOffset, optional boolean littleEndian);
     [RaisesException] double getFloat64(unsigned long byteOffset, optional boolean littleEndian);
 
     [RaisesException] void setInt8(unsigned long byteOffset, byte value);
     [RaisesException] void setUint8(unsigned long byteOffset, octet value);
 
     [RaisesException] void setInt16(unsigned long byteOffset, short value, optional boolean littleEndian);
     [RaisesException] void setUint16(unsigned long byteOffset, unsigned short value, optional boolean littleEndian);
     [RaisesException] void setInt32(unsigned long byteOffset, long value, optional boolean littleEndian);
     [RaisesException] void setUint32(unsigned long byteOffset, unsigned long value, optional boolean littleEndian);
     [RaisesException] void setFloat32(unsigned long byteOffset, float value, optional boolean littleEndian);
     [RaisesException] void setFloat64(unsigned long byteOffset, double value, optional boolean littleEndian);
 };