Don't include scroll offset in offsetFromLayoutObject for scrolling contents layers.

third_party/WebKit/LayoutTests/platform/linux/paint/selection/selection-within-composited-scroller-expected.txt

 {
   "bounds": [800, 600],
   "children": [
     {
       "bounds": [800, 600],
       "contentsOpaque": true,
       "drawsContent": true,
       "paintInvalidations": [
         {
           "object": "LayoutBlockFlow BODY",
           "reason": "selection"
         },
         {
           "object": "LayoutBlockFlow HTML",
           "reason": "selection"
         }
       ],
       "children": [
         {
           "position": [8, 8],
           "bounds": [200, 200],
           "contentsOpaque": true,
           "shouldFlattenTransform": false,
           "drawsContent": true,
           "backgroundColor": "#D3D3D3",
           "paintInvalidations": [
             {
-              "object": "LayoutText #text",
-              "rect": [0, 160, 21, 19],
-              "reason": "selection"
-            },
-            {
               "object": "InlineTextBox 'test'",
               "reason": "selection"
             },
             {
               "object": "LayoutBlockFlow DIV id='scroller'",
               "reason": "selection"
             },
             {
               "object": "LayoutBlockFlow DIV id='target'",
               "reason": "selection"
+            },
+            {
+              "object": "LayoutText #text",
+              "reason": "selection"
             }
           ],
           "children": [
             {
               "bounds": [185, 185],
               "shouldFlattenTransform": false,
               "children": [
                 {
                   "bounds": [200, 1620],
                   "drawsContent": true,
@@ skipping 37 matching lines @@
                 }
               ]
             }
           ]
         }
       ]
     }
   ]
 }