Re-land of: Make the compositing assert disabler for paint invalidation more targeted.

Now with assert disabler in WebPluginContainerImpl, to fix call sites from plugins.

BUG=360286

Review URL: https://codereview.chromium.org/524473003

git-svn-id: svn://svn.chromium.org/blink/trunk@181335 bbb929c8-8fbe-4397-9dbb-9b2b20218538