Unify all types of overflow-related clips for paint and hit testing.

third_party/WebKit/LayoutTests/platform/mac-mac10.9/paint/invalidation/control-clip-expected.txt

 {
   "layers": [
     {
       "name": "LayoutView #document",
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow (anonymous)",
-          "rect": [9, 84, 198, 14],
+          "rect": [9, 85, 198, 13],
           "reason": "forced by layout"
         },
         {
           "object": "LayoutBlockFlow (anonymous)",
           "rect": [16, 114, 184, 13],
           "reason": "forced by layout"
         },
         {
           "object": "LayoutText #text",
           "rect": [84, 114, 48, 13],
           "reason": "full"
         },
         {
           "object": "LayoutText (anonymous)",
-          "rect": [9, 84, 47, 14],
+          "rect": [9, 85, 47, 13],
           "reason": "full"
         }
       ]
     }
   ],
   "objectPaintInvalidations": [
     {
       "object": "LayoutBlockFlow (anonymous)",
       "reason": "forced by layout"
     },
@@ skipping 21 matching lines @@
       "object": "LayoutText #text",
       "reason": "full"
     },
     {
       "object": "InlineTextBox 'SUCCESS'",
       "reason": "full"
     }
   ]
 }