Revert 182690 "Fix for accelerated canvas layer content invalida..."

Reason for revert: fix was meant specifically for M38 branch.
Reverting from trunk, now that fix was merged.
> Fix for accelerated canvas layer content invalidation
> 
> The fixes a display invalidation bug that exists only in M-38
> This change must be reverted from trunk after it is merged to
> the release branch.  This change disables a renctly added
> optimization that that performs partial display invalidations
> on 2d canvas layers.
> 
> BUG=417201
> 
> Review URL: https://codereview.chromium.org/601183004

TBR=junov@chromium.org

Review URL: https://codereview.chromium.org/604823004

git-svn-id: svn://svn.chromium.org/blink/trunk@182711 bbb929c8-8fbe-4397-9dbb-9b2b20218538