Add failing expectations for a number of  canvas, SVG and webaudio tests on Linux

BUG=252052
TBR=apatrick

Review URL: https://codereview.chromium.org/17175015

git-svn-id: svn://svn.chromium.org/blink/trunk@152739 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Disallow focusing of inert elements.

This patch modifies Node::isFocusable to be inert-aware. 
It also changes isInert to walk up ancestor frames;
otherwise, elements inside inert iframes would not be
considered inert.

One layout test in this patch,
fast/dom/HTMLDialogElement/modal-dialog-blocks-focus.html,
is based on the test fast/events/tabindex-focus-blur-all.html

BUG=242848

Review URL: https://chromiumcodereview.appspot.com/16739018

git-svn-id: svn://svn.chromium.org/blink/trunk@152740 bbb929c8-8fbe-4397-9dbb-9b2b20218538