Merge 91797 - Add support for download='filename' attribute in anchors.

LayoutTests/platform/mac/Skipped

 #
 # Copyright (C) 2008 Apple 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:
 #
 # 1.  Redistributions of source code must retain the above copyright
 #     notice, this list of conditions and the following disclaimer. 
 # 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 323 matching lines @@
 http/tests/inspector/network/network-disable-cache-xhrs.html
 
 # https://bugs.webkit.org/show_bug.cgi?id=58515
 compositing/overflow/clip-content-under-overflow-controls.html
 
 # Quota API is not supported.
 storage/storageinfo-query-usage.html
 storage/storageinfo-request-quota.html
 storage/storageinfo-no-callbacks.html
 
+# Tests that require ENABLE(DOWNLOAD_ATTRIBUTE).
+fast/dom/HTMLAnchorElement/anchor-nodownload.html
+fast/dom/HTMLAnchorElement/anchor-download.html
+fast/dom/HTMLAnchorElement/anchor-nodownload-set.html
+fast/dom/HTMLAnchorElement/anchor-download-unset.html
+
 # Expose title direction in WebKit API
 # https://bugs.webkit.org/show_bug.cgi?id=58845
 fast/dom/title-directionality.html
 
 # Timing out for unknown reasons.  Passes on Chromium, QT and GTK+.
 # https://bugs.webkit.org/show_bug.cgi?id=58924
 plugins/mouse-click-iframe-to-plugin.html
 
 # Animation API is disabled by default
 animations/animation-api-1.html
@@ skipping 32 matching lines @@
 http/tests/security/isolatedWorld/cross-origin-xhr.html
 
 # https://bugs.webkit.org/show_bug.cgi?id=63282 layerTreeAsText doesn't work for iframes
 compositing/rtl/rtl-iframe-absolute-overflow-scrolled.html
 compositing/rtl/rtl-iframe-absolute-overflow.html
 compositing/rtl/rtl-iframe-absolute.html
 compositing/rtl/rtl-iframe-fixed-overflow-scrolled.html
 compositing/rtl/rtl-iframe-fixed-overflow.html
 compositing/rtl/rtl-iframe-fixed.html
 compositing/rtl/rtl-iframe-relative.html