Add saveImageFromDataURL() and use it in saveImageAt().

Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 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 3278 matching lines @@
         // FIXME: implement a cache of the most recent HitTestResult to avoid having
         //        to do two hit tests.
         return;
     }
 
     m_page->deprecatedLocalMainFrame()->editor().copyImage(result);
 }
 
 void WebViewImpl::saveImageAt(const WebPoint& point)
 {
-    if (!m_page)
+    if (!m_client)
         return;
 
-    KURL url = hitTestResultForWindowPos(point).absoluteImageURLIncludingCanvasDataURL();
-
-    if (url.isEmpty())
+    Node* node = hitTestResultForWindowPos(point).innerNonSharedNode();
+    if (!node || !(isHTMLCanvasElement(*node) || isHTMLImageElement(*node)))
         return;
 
-    ResourceRequest request(url);
-    request.setRequestContext(WebURLRequest::RequestContextDownload);
-    m_page->deprecatedLocalMainFrame()->loader().client()->loadURLExternally(
-        request, NavigationPolicyDownloadTo, WebString());
+    m_client->saveImageFromDataURL(toElement(*node).imageSourceURL());

[Justin Novosad, 2014/09/03 16:55:29]

The name "saveImageFromDataURL" is misleading. The imageSourceURL will not be a
data URL is the node is an image element. That should be fixed in the companion
chromium-side change.

[Ken Russell (switch to Gerrit), 2014/09/04 00:23:10]

After considering the various alternatives I think this code should invoke the
old code path for images, and use this new API only for data: URLs. That has the
least possible security impact. It should still allow some of the old code to be
deleted; just not the NavigationPolicyDownloadTo enum.

 }
 
 void WebViewImpl::dragSourceEndedAt(
     const WebPoint& clientPoint,
     const WebPoint& screenPoint,
     WebDragOperation operation)
 {
     PlatformMouseEvent pme(clientPoint, screenPoint, LeftButton, PlatformEvent::MouseMoved,
         0, false, false, false, false, PlatformMouseEvent::RealOrIndistinguishable, 0);
     m_page->deprecatedLocalMainFrame()->eventHandler().dragSourceEndedAt(pme,
@@ skipping 953 matching lines @@
     const PageScaleConstraints& constraints = m_pageScaleConstraintsSet.pageDefinedConstraints();
 
     if (!mainFrameImpl() || !mainFrameImpl()->frameView())
         return false;
 
     return mainFrameImpl()->frameView()->layoutSize().width() == m_size.width
         || (constraints.minimumScale == constraints.maximumScale && constraints.minimumScale != -1);
 }
 
 } // namespace blink