Remove some flaky tests that aren't flaky anymore

These entries don't show up as flaky in the flakiness dashboard
so let's remove them from the expectations.

TBR=haraken
BUG=43890,49970,52017,52572

Review URL: https://codereview.chromium.org/14303002

git-svn-id: svn://svn.chromium.org/blink/trunk@148484 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Attempt to fix windows build

Windows doesn't like GYP referencing files that do not exist.

TBR=eseidel

Review URL: https://codereview.chromium.org/13945022

git-svn-id: svn://svn.chromium.org/blink/trunk@148485 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make TextTrackCueBox inherit from HTMLDivElement.

TextTrackCueBox will be wrapped with bindings appropriate for a
div element, so it had better inherit from it -- or else.

BUG=231667

Review URL: https://codereview.chromium.org/13985031

git-svn-id: svn://svn.chromium.org/blink/trunk@148486 bbb929c8-8fbe-4397-9dbb-9b2b20218538