Implement "Copy image" for canvas (blink side).

Source/core/editing/Editor.cpp

Index: Source/core/editing/Editor.cpp
diff --git a/Source/core/editing/Editor.cpp b/Source/core/editing/Editor.cpp
index 01b7554bca9700dce716dd382c9acc41252bb6b9..61b912ba19b4ddd92d49da556d78626c9b6e932c 100644
--- a/Source/core/editing/Editor.cpp
+++ b/Source/core/editing/Editor.cpp
@@ -68,6 +68,7 @@
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/frame/UseCounter.h"
+#include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLImageElement.h"
 #include "core/html/HTMLInputElement.h"
 #include "core/html/HTMLTextAreaElement.h"
@@ -420,20 +421,38 @@ void Editor::writeSelectionToPasteboard(Pasteboard* pasteboard, Range* selectedR
     pasteboard->writeHTML(html, url, plainText, canSmartCopyOrDelete());
 }
 
+static Image* imageFromNode(const Node* node)
+{
+    node->document().updateLayoutIgnorePendingStylesheets();
+    RenderObject* renderer = node->renderer();
+    if (!renderer)
+        return 0;
+
+    if (renderer->isCanvas()) {

[yosin_UTC9, 2014/06/30 09:17:08]

nit: We don't need to have "{}" for single then clause.

[zino, 2014/06/30 10:30:32]

Done.

+        return toHTMLCanvasElement(node)->copiedImage();
+    }
+    if (renderer->isImage()) {
+        RenderImage* renderImage = toRenderImage(renderer);
+        if (!renderImage)
+            return 0;

[yosin_UTC9, 2014/06/30 09:17:08]

optional nit: It is better to use |nullptr|.

[zino, 2014/06/30 10:30:32]

Done.
I also think it is better.
BTW, can we use it? (Blink coding guideline says to have to use 0 in C++ yet)

+
+        ImageResource* cachedImage = renderImage->cachedImage();
+        if (!cachedImage || cachedImage->errorOccurred())
+            return 0;
+        return cachedImage->imageForRenderer(renderImage);
+    }
+
+    return 0;
+}
+
 static void writeImageNodeToPasteboard(Pasteboard* pasteboard, Node* node, const String& title)
 {
     ASSERT(pasteboard);
     ASSERT(node);
 
-    if (!(node->renderer() && node->renderer()->isImage()))
-        return;
-
-    RenderImage* renderer = toRenderImage(node->renderer());
-    ImageResource* cachedImage = renderer->cachedImage();
-    if (!cachedImage || cachedImage->errorOccurred())
+    Image* image = imageFromNode(node);
+    if (!image)
         return;
-    Image* image = cachedImage->imageForRenderer(renderer);
-    ASSERT(image);
 
     // FIXME: This should probably be reconciled with HitTestResult::absoluteImageURL.
     AtomicString urlString;
@@ -441,7 +460,7 @@ static void writeImageNodeToPasteboard(Pasteboard* pasteboard, Node* node, const
         urlString = toElement(node)->getAttribute(srcAttr);
     else if (isSVGImageElement(*node))
         urlString = toElement(node)->getAttribute(XLinkNames::hrefAttr);
-    else if (isHTMLEmbedElement(*node) || isHTMLObjectElement(*node))
+    else if (isHTMLEmbedElement(*node) || isHTMLObjectElement(*node) || isHTMLCanvasElement(*node))
         urlString = toElement(node)->imageSourceURL();
     KURL url = urlString.isEmpty() ? KURL() : node->document().completeURL(stripLeadingAndTrailingHTMLSpaces(urlString));