Adds WebElement::imageContents()

Source/web/WebNode.cpp

 /*
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 31 matching lines @@
 #include "WebPluginContainer.h"
 #include "WebPluginContainerImpl.h"
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/dom/Event.h"
 #include "core/dom/Node.h"
 #include "core/dom/NodeList.h"
 #include "core/editing/markup.h"
 #include "core/page/Frame.h"
 #include "core/platform/Widget.h"
+#include "core/rendering/RenderImage.h"
 #include "core/rendering/RenderObject.h"
 #include "core/rendering/RenderWidget.h"
 #include "public/platform/WebString.h"
 #include "public/platform/WebVector.h"
 
 using namespace WebCore;
 
 namespace WebKit {
 
 void WebNode::reset()
@@ skipping 182 matching lines @@
 }
 
 WebElement WebNode::shadowHost() const
 {
     if (isNull())
         return WebElement();
     const Node* coreNode = constUnwrap<Node>();
     return WebElement(coreNode->shadowHost());
 }
 
+WebImage WebNode::imageContents()
+{
+    if (isNull())
+        return WebImage();
+
+    RefPtr<Node> node = unwrap<Node>();
+
+    if (!(node->renderer() && node->renderer()->isImage()))
+        return WebImage();
+
+    WebCore::RenderImage* renderer = toRenderImage(node->renderer());
+    WebCore::CachedImage* cachedImage = renderer->cachedImage();
+    if (!cachedImage || cachedImage->errorOccurred())
+        return WebImage();
+    WebCore::Image* image = cachedImage->imageForRenderer(renderer);

[esprehn, 2013/07/25 22:52:03]

This should be a method on HTMLImageElement and this code should check
isHTMLImageElement(node) and then cast to that and then do image->imageData() or
something like that.

We're trying to get people to stop digging down into the render tree like this.

[jamesr, 2013/07/26 17:54:33]

I don't follow.  This line isn't reaching into the render tree.  We do access
the renderer on line 265, but that's type checked. 
CachedImage::imageForRenderer() is the same as CachedImage::image() except that
it also checks for the image in the SVG image cache (which is keyed by
RenderObject*, for whatever reason) if the image is an SVG image.

If we instead got to the CachedImage by downcasting the Node to HTMLImageElement
this code wouldn't for for elements that generate RenderImages but aren't
HTMLImageElement.  Today, that means HTMLPlugInImageElement and ImageInputType. 
Maybe that'd be OK but it is less general.

+    ASSERT(image);
+
+    RefPtr<NativeImageSkia> bitmap = image->nativeImageForCurrentFrame();
+    if (!bitmap)
+        return WebImage();
+
+    return bitmap->bitmap();
+}
+
 WebNode::WebNode(const PassRefPtr<Node>& node)
     : m_private(node)
 {
 }
 
 WebNode& WebNode::operator=(const PassRefPtr<Node>& node)
 {
     m_private = node;
     return *this;
 }
 
 WebNode::operator PassRefPtr<Node>() const
 {
     return m_private.get();
 }
 
 } // namespace WebKit