Make PaintInvalidationFull more specific based on document cycle
    
When debugging repaint storms, we may want to know in which stage
the shouldDoFullPaintInvalidation flag is set.
    
Make PaintInvalidationFull more specific based on document cycle
with 3 new PaintInvalidationReasons:
- PaintInvalidationStyleChange
- PaintInvalidationForcedByLayout
- PaintInvalidationCompositingUpdate    

BUG=410465
TBR=esprehn@chromium.org (Source/platform/graphics/PaintInvalidationReason.h)

Review URL: https://codereview.chromium.org/645673002

git-svn-id: svn://svn.chromium.org/blink/trunk@184742 bbb929c8-8fbe-4397-9dbb-9b2b20218538