Remove unused FileSystem-related methods in WebFrame

Post-refactoring cleanup for
https://src.chromium.org/viewvc/blink?revision=167757&view=revision

BUG=none

Review URL: https://codereview.chromium.org/183083002

git-svn-id: svn://svn.chromium.org/blink/trunk@168082 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove unused RenderBoxModelObject::highQualityRepaintTimerFired

This very complex patch removes the unused highQualityRepaintTimerFired
function on RenderBoxModelObject.

BUG=

Review URL: https://codereview.chromium.org/183773004

git-svn-id: svn://svn.chromium.org/blink/trunk@168083 bbb929c8-8fbe-4397-9dbb-9b2b20218538