Fix a crash in WebViewImpl::copyImageAt.

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index 979a54dd8efe30cf60b7b1844cdc3f8a1b9e9274..d182a10a314c26df757261cd62baa214314b5365 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -3450,10 +3450,7 @@ void WebViewImpl::copyImageAt(const WebPoint& point)
         return;
 
     HitTestResult result = hitTestResultForWindowPos(point);
-    Node* node = result.innerNonSharedNode();
-    ASSERT(node);
-
-    if (!isHTMLCanvasElement(*node) && result.absoluteImageURL().isEmpty()) {
+    if (!isHTMLCanvasElement(result.innerNonSharedNode()) && result.absoluteImageURL().isEmpty()) {
         // There isn't actually an image at these coordinates.  Might be because
         // the window scrolled while the context menu was open or because the page
         // changed itself between when we thought there was an image here and when