Implement wouldTaintOrigin and expose createPattern for OCRC2D on main thread

third_party/WebKit/Source/core/html/canvas/CanvasRenderingContext.cpp

 /*
  * Copyright (C) 2009 Apple 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
@@ skipping 42 matching lines @@
     return ContextTypeCount;
 }
 
 CanvasRenderingContext::ContextType CanvasRenderingContext::resolveContextTypeAliases(CanvasRenderingContext::ContextType type)
 {
     if (type == ContextExperimentalWebgl)
         return ContextWebgl;
     return type;
 }
 
-bool CanvasRenderingContext::wouldTaintOrigin(CanvasImageSource* imageSource)
+bool CanvasRenderingContext::wouldTaintOrigin(CanvasImageSource* imageSource, SecurityOrigin* destinationSecurityOrigin)
 {
     const KURL& sourceURL = imageSource->sourceURL();
     bool hasURL = (sourceURL.isValid() && !sourceURL.isAboutBlankURL());
 
     if (hasURL) {
         if (sourceURL.protocolIsData() || m_cleanURLs.contains(sourceURL.getString()))
             return false;
         if (m_dirtyURLs.contains(sourceURL.getString()))
             return true;
     }
 
-    bool taintOrigin = imageSource->wouldTaintOrigin(canvas()->getSecurityOrigin());
+    ASSERT(!canvas() == !!destinationSecurityOrigin); // Must have one or the other
+    bool taintOrigin = imageSource->wouldTaintOrigin(destinationSecurityOrigin ? destinationSecurityOrigin : canvas()->getSecurityOrigin());
 
     if (hasURL) {
         if (taintOrigin)
             m_dirtyURLs.add(sourceURL.getString());
         else
             m_cleanURLs.add(sourceURL.getString());
     }
     return taintOrigin;
 }
 
 DEFINE_TRACE(CanvasRenderingContext)
 {
     visitor->trace(m_canvas);
     visitor->trace(m_offscreenCanvas);
 }
 
 } // namespace blink