Simplify application of perspective origin.

LayoutTests/platform/linux/compositing/overflow/selection-gaps-toggling-expected.txt

Index: LayoutTests/platform/linux/compositing/overflow/selection-gaps-toggling-expected.txt
diff --git a/LayoutTests/platform/linux/compositing/overflow/selection-gaps-toggling-expected.txt b/LayoutTests/platform/linux/compositing/overflow/selection-gaps-toggling-expected.txt
index 10b4bbdcef9456038a9cb99f862780402fc6ad10..691a1a72aa9021214b1b25e9b62e1c99b8e7986a 100644
--- a/LayoutTests/platform/linux/compositing/overflow/selection-gaps-toggling-expected.txt
+++ b/LayoutTests/platform/linux/compositing/overflow/selection-gaps-toggling-expected.txt
@@ -31,10 +31,9 @@ Lorem Ipsum
               "children": [
                 {
                   "bounds": [285, 665],
-                  "shouldFlattenTransform": false,
                   "children": [
                     {
-                      "shouldFlattenTransform": false
+
                     }
                   ]
                 }
@@ -140,10 +139,10 @@ Lorem Ipsum
 *** iteration 2: ***
 
 {
-  "bounds": [785, 2610],
+  "bounds": [785, 2594],
   "children": [
     {
-      "bounds": [785, 2610],
+      "bounds": [785, 2594],
       "contentsOpaque": true,
       "drawsContent": true,
       "children": [
@@ -157,12 +156,10 @@ Lorem Ipsum
               "children": [
                 {
                   "bounds": [285, 665],
-                  "shouldFlattenTransform": false,
                   "children": [
                     {
                       "position": [0, 195],
                       "bounds": [285, 15],
-                      "shouldFlattenTransform": false,
                       "drawsContent": true
                     }
                   ]
@@ -269,10 +266,10 @@ Lorem Ipsum
 *** iteration 3: ***
 
 {
-  "bounds": [785, 4674],
+  "bounds": [785, 4626],
   "children": [
     {
-      "bounds": [785, 4674],
+      "bounds": [785, 4626],
       "contentsOpaque": true,
       "drawsContent": true,
       "children": [
@@ -286,12 +283,10 @@ Lorem Ipsum
               "children": [
                 {
                   "bounds": [285, 665],
-                  "shouldFlattenTransform": false,
                   "children": [
                     {
                       "position": [0, 195],
-                      "bounds": [285, 15],
-                      "shouldFlattenTransform": false
+                      "bounds": [285, 15]
                     }
                   ]
                 }