Use reference for paintInvalidationContainer param of invalidatePaintIfNeeded

BTW also change getPaintInvalidationReason, incrementallyInvalidatePaint
and fullyInvalidatePaint which are called only by
invalidatePaintIfNeeded.

Review URL: https://codereview.chromium.org/374833007

git-svn-id: svn://svn.chromium.org/blink/trunk@177694 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Auto-rebaseline for r177621

http://src.chromium.org/viewvc/blink?view=revision&revision=177621

BUG=363834
TBR=leviw@chromium.org

Review URL: https://codereview.chromium.org/375823004

git-svn-id: svn://svn.chromium.org/blink/trunk@177695 bbb929c8-8fbe-4397-9dbb-9b2b20218538