Paint local background colors onto foreground layer.

third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-with-transparent-background-expected.txt

Index: third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-with-transparent-background-expected.txt
diff --git a/third_party/WebKit/LayoutTests/virtual/prefer_compositing_to_lcd_text/compositing/overflow/overflow-auto-with-touch-toggle-expected.txt b/third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-with-transparent-background-expected.txt
similarity index 71%
copy from third_party/WebKit/LayoutTests/virtual/prefer_compositing_to_lcd_text/compositing/overflow/overflow-auto-with-touch-toggle-expected.txt
copy to third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-with-transparent-background-expected.txt
index 4288656dee7cab9c6fc711ed3ff81cc26882ed80..172b25877cc7af377f759371b02e68bfeda2aa80 100644
--- a/third_party/WebKit/LayoutTests/virtual/prefer_compositing_to_lcd_text/compositing/overflow/overflow-auto-with-touch-toggle-expected.txt
+++ b/third_party/WebKit/LayoutTests/compositing/overflow/overflow-scroll-with-transparent-background-expected.txt
@@ -9,41 +9,43 @@
       "drawsContent": true,
       "children": [
         {
-          "name": "LayoutBlockFlow DIV class='scroller'",
+          "name": "LayoutBlockFlow DIV id='scroller'",
           "position": [8, 8],
-          "bounds": [300, 300],
+          "bounds": [220, 220],
           "shouldFlattenTransform": false,
           "drawsContent": true,
+          "backgroundColor": "#FFFFFF",
           "children": [
             {
               "name": "Scrolling Layer",
-              "bounds": [285, 285],
+              "position": [10, 10],
+              "bounds": [185, 185],
               "shouldFlattenTransform": false,
               "children": [
                 {
                   "name": "Scrolling Contents Layer",
-                  "bounds": [1000, 1000],
+                  "bounds": [185, 300],
                   "drawsContent": true
                 }
               ]
             },
             {
               "name": "Overflow Controls Host Layer",
-              "bounds": [300, 300],
+              "bounds": [220, 220],
               "children": [
                 {
                   "name": "Horizontal Scrollbar Layer",
-                  "position": [0, 285],
-                  "bounds": [285, 15]
+                  "position": [10, 195],
+                  "bounds": [185, 15]
                 },
                 {
                   "name": "Vertical Scrollbar Layer",
-                  "position": [285, 0],
-                  "bounds": [15, 285]
+                  "position": [195, 10],
+                  "bounds": [15, 185]
                 },
                 {
                   "name": "Scroll Corner Layer",
-                  "position": [285, 285],
+                  "position": [195, 195],
                   "bounds": [15, 15],
                   "drawsContent": true
                 }