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

Source/web/ContextMenuClientImpl.cpp

Index: Source/web/ContextMenuClientImpl.cpp
diff --git a/Source/web/ContextMenuClientImpl.cpp b/Source/web/ContextMenuClientImpl.cpp
index 7dbf1ba9dadf60efe4f03278582e41497e11a5f7..64a2f995e79948058736a9deb19e126e51f23b7c 100644
--- a/Source/web/ContextMenuClientImpl.cpp
+++ b/Source/web/ContextMenuClientImpl.cpp
@@ -225,10 +225,15 @@ void ContextMenuClientImpl::showContextMenu(const WebCore::ContextMenu* defaultM
 
     if (isHTMLCanvasElement(r.innerNonSharedNode())) {
         data.mediaType = WebContextMenuData::MediaTypeCanvas;
+        data.hasImageContents = true;
     } else if (!r.absoluteImageURL().isEmpty()) {
         data.srcURL = r.absoluteImageURL();
         data.mediaType = WebContextMenuData::MediaTypeImage;
         data.mediaFlags |= WebContextMenuData::MediaCanPrint;
+
+        // An image can be null for many reasons, like being blocked, no image
+        // data received from server yet.
+        data.hasImageContents = r.image() && !r.image()->isNull();
     } else if (!r.absoluteMediaURL().isEmpty()) {
         data.srcURL = r.absoluteMediaURL();
 
@@ -288,12 +293,6 @@ void ContextMenuClientImpl::showContextMenu(const WebCore::ContextMenu* defaultM
         }
     }
 
-    // An image can to be null for many reasons, like being blocked, no image
-    // data received from server yet.
-    data.hasImageContents =
-        (data.mediaType == WebContextMenuData::MediaTypeImage)
-        && r.image() && !(r.image()->isNull());
-
     // If it's not a link, an image, a media element, or an image/media link,
     // show a selection menu or a more generic page menu.
     if (selectedFrame->document()->loader())