Implement select listbox using shadow DOM

LayoutTests/platform/mac/fast/forms/listbox-hit-test-zoomed-expected.txt

Index: LayoutTests/platform/mac/fast/forms/listbox-hit-test-zoomed-expected.txt
diff --git a/LayoutTests/platform/mac/fast/forms/listbox-hit-test-zoomed-expected.txt b/LayoutTests/platform/mac/fast/forms/listbox-hit-test-zoomed-expected.txt
index 142af25c47dda4543c1a56fc377b1ce396e754b0..c11b73dbe5fc065c14a260dd10490a5a1e9795ae 100644
--- a/LayoutTests/platform/mac/fast/forms/listbox-hit-test-zoomed-expected.txt
+++ b/LayoutTests/platform/mac/fast/forms/listbox-hit-test-zoomed-expected.txt
@@ -4,7 +4,6 @@ layer at (0,0) size 800x600
   RenderBlock {HTML} at (0,0) size 800x600
     RenderBody {BODY} at (9.59,9.59) size 780.81x580.81
       RenderBlock (anonymous) at (0,0) size 780.81x162
-        RenderListBox {SELECT} at (0,0) size 128x162 [bgcolor=#FFFFFF] [border: (12px solid #000000)]
         RenderText {#text} at (0,0) size 0x0
       RenderBlock {DIV} at (0,162) size 780.81x66
         RenderText {#text} at (0,0) size 61x22
@@ -15,3 +14,56 @@ layer at (0,0) size 800x600
         RenderBR {BR} at (106,39) size 0x0
         RenderText {#text} at (0,44) size 106x22
           text run at (0,44) width 106: "Test 2 Passed"
+layer at (10,10) size 128x162 clip at (22,22) size 93x138 scrollY 6 scrollHeight 316
+  RenderListBox {SELECT} at (0,0) size 128.09x162 [bgcolor=#FFFFFF] [border: (12px solid #000000)]
+    RenderBlock {OPTION} at (24,24) size 69.09x17.19
+      RenderText {#text} at (2,0) size 25x16
+        text run at (2,0) width 25: "one"
+    RenderBlock {OPTION} at (24,41.19) size 69.09x17.19
+      RenderText {#text} at (2,0) size 24x16
+        text run at (2,0) width 24: "two"
+    RenderBlock {OPTION} at (24,58.38) size 69.09x17.19
+      RenderText {#text} at (2,0) size 34x16
+        text run at (2,0) width 34: "three"
+    RenderBlock {OPTION} at (24,75.56) size 69.09x17.19
+      RenderText {#text} at (2,0) size 27x16
+        text run at (2,0) width 27: "four"
+    RenderBlock {OPTION} at (24,92.75) size 69.09x17.19
+      RenderText {#text} at (2,0) size 24x16
+        text run at (2,0) width 24: "five"
+    RenderBlock {OPTION} at (24,109.94) size 69.09x17.19
+      RenderText {#text} at (2,0) size 20x16
+        text run at (2,0) width 20: "six"
+    RenderBlock {OPTION} at (24,127.13) size 69.09x17.19 [color=#FFFFFF] [bgcolor=#3875D7]
+      RenderText {#text} at (2,0) size 37x16
+        text run at (2,0) width 37: "seven"
+    RenderBlock {OPTION} at (24,144.31) size 69.09x17.19
+      RenderText {#text} at (2,0) size 33x16
+        text run at (2,0) width 33: "eight"
+    RenderBlock {OPTION} at (24,161.50) size 69.09x17.19
+      RenderText {#text} at (2,0) size 28x16
+        text run at (2,0) width 28: "nine"
+    RenderBlock {OPTION} at (24,178.69) size 69.09x17.19
+      RenderText {#text} at (2,0) size 21x16
+        text run at (2,0) width 21: "ten"
+    RenderBlock {OPTION} at (24,195.88) size 69.09x17.19
+      RenderText {#text} at (2,0) size 42x16
+        text run at (2,0) width 42: "eleven"
+    RenderBlock {OPTION} at (24,213.06) size 69.09x17.19
+      RenderText {#text} at (2,0) size 41x16
+        text run at (2,0) width 41: "twelve"
+    RenderBlock {OPTION} at (24,230.25) size 69.09x17.19
+      RenderText {#text} at (2,0) size 51x16
+        text run at (2,0) width 51: "thirteen"
+    RenderBlock {OPTION} at (24,247.44) size 69.09x17.19
+      RenderText {#text} at (2,0) size 55x16
+        text run at (2,0) width 55: "fourteen"
+    RenderBlock {OPTION} at (24,264.63) size 69.09x17.19
+      RenderText {#text} at (2,0) size 42x16
+        text run at (2,0) width 42: "fifteen"
+    RenderBlock {OPTION} at (24,281.81) size 69.09x17.19
+      RenderText {#text} at (2,0) size 47x16
+        text run at (2,0) width 47: "sixteen"
+    RenderBlock {OPTION} at (24,299) size 69.09x17.19
+      RenderText {#text} at (2,0) size 65x16
+        text run at (2,0) width 65: "seventeen"