Switch HTMLCanvasElement over to new-style ExceptionState.

Source/core/html/HTMLCanvasElement.cpp

 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. 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.
@@ skipping 355 matching lines @@
     // FIXME: Make isSupportedImageMIMETypeForEncoding threadsafe (to allow this method to be used on a worker thread).
     if (mimeType.isNull() || !MIMETypeRegistry::isSupportedImageMIMETypeForEncoding(lowercaseMimeType))
         lowercaseMimeType = "image/png";
 
     return lowercaseMimeType;
 }
 
 String HTMLCanvasElement::toDataURL(const String& mimeType, const double* quality, ExceptionState& exceptionState)
 {
     if (!m_originClean) {
-        exceptionState.throwSecurityError(ExceptionMessages::failedToExecute("toDataURL", "HTMLCanvasElement", "tainted canvases may not be exported."));
+        exceptionState.throwSecurityError("tainted canvases may not be exported.");

[Mike West, 2013/11/29 08:26:45]

Nit: If you're changing this anyway, can you capitalize "Tainted"?

[sof, 2013/11/29 08:58:03]

Done, and same for the other taint-related error messages.

(Will assume ok and proceed to commit.)

         return String();
     }
 
     if (m_size.isEmpty() || !buffer())
         return String("data:,");
 
     String encodingMimeType = toEncodingMimeType(mimeType);
 
     // Try to get ImageData first, as that may avoid lossy conversions.
     RefPtr<ImageData> imageData = getImageData();
@@ skipping 164 matching lines @@
     ASSERT(hasImageBuffer() && !m_didFailToCreateImageBuffer);
     IntSize unscaledSize = size();
     IntSize size = convertLogicalToDevice(unscaledSize);
     AffineTransform transform;
     if (size.width() && size.height())
         transform.scaleNonUniform(size.width() / unscaledSize.width(), size.height() / unscaledSize.height());
     return m_imageBuffer->baseTransform() * transform;
 }
 
 }