Implement HTMLMarqueeElement's animation in private scripts

LayoutTests/platform/linux/fast/inline-block/003-expected.txt

Index: LayoutTests/platform/linux/fast/inline-block/003-expected.txt
diff --git a/LayoutTests/platform/linux/fast/inline-block/003-expected.txt b/LayoutTests/platform/linux/fast/inline-block/003-expected.txt
index 7d50c077564d93f1ecb520150ec5c084a53503af..4f95969dcd7bb5961bb1161eaf647932ca896b1f 100644
--- a/LayoutTests/platform/linux/fast/inline-block/003-expected.txt
+++ b/LayoutTests/platform/linux/fast/inline-block/003-expected.txt
@@ -3,10 +3,10 @@ layer at (0,0) size 800x600
 layer at (0,0) size 800x600
   RenderBlock {HTML} at (0,0) size 800x600
     RenderBody {BODY} at (8,8) size 784x584
-      RenderBlock (anonymous) at (0,0) size 784x20
+      RenderBlock {P} at (0,0) size 784x20
         RenderText {#text} at (0,0) size 498x19
           text run at (0,0) width 498: "The two divs below should be on the same line, since they are display: inline-block."
-      RenderBlock {CENTER} at (0,20) size 784x24
+      RenderBlock {CENTER} at (0,36) size 784x24
         RenderBlock {DIV} at (88,0) size 304x24 [border: (2px solid #0000FF)]
           RenderText {#text} at (107,2) size 90x19
             text run at (107,2) width 90: "This is div one."
@@ -14,19 +14,28 @@ layer at (0,0) size 800x600
           RenderText {#text} at (106,2) size 92x19
             text run at (106,2) width 92: "This is div two."
         RenderText {#text} at (0,0) size 0x0
-      RenderBlock (anonymous) at (0,44) size 784x68
+      RenderBlock {P} at (0,76) size 784x20
         RenderText {#text} at (0,0) size 691x19
           text run at (0,0) width 691: "The two marquees below should be on separate lines, since marquees fill the width of a containing block by default."
+      RenderBlock {P} at (0,112) size 784x40
+        RenderText {#text} at (0,0) size 782x39
+          text run at (0,0) width 782: "This test uses white characters to make the result image deterministic. (Otherwise, the result image changes depending on when the"
+          text run at (0,20) width 552: "content_shell takes a snapshot.) In order to run this test manually, change the color to black."
+      RenderBlock (anonymous) at (0,168) size 784x48
         RenderInline {SPAN} at (0,0) size 784x43
           RenderText {#text} at (0,0) size 0x0
           RenderText {#text} at (0,0) size 0x0
           RenderText {#text} at (0,0) size 0x0
         RenderText {#text} at (0,0) size 0x0
-layer at (8,72) size 784x24 clip at (10,74) size 780x20 scrollX -765
-  RenderMarquee {MARQUEE} at (0,20) size 784x24 [border: (2px solid #008000)]
-    RenderText {#text} at (2,2) size 90x19
-      text run at (2,2) width 90: "This is div one."
-layer at (8,96) size 784x24 clip at (10,98) size 780x20 scrollX -765
-  RenderMarquee {MARQUEE} at (0,44) size 784x24 [border: (2px solid #008000)]
-    RenderText {#text} at (2,2) size 91x19
-      text run at (2,2) width 91: "This is div two."
+layer at (8,176) size 784x24 clip at (10,178) size 780x20
+  RenderBlock {MARQUEE} at (0,0) size 784x24 [border: (2px solid #008000)]
+    RenderBlock {DIV} at (2,2) size 780x20
+      RenderInline {SPAN} at (0,0) size 90x19 [color=#FFFFFF]
+        RenderText {#text} at (0,0) size 90x19
+          text run at (0,0) width 90: "This is div one."
+layer at (8,200) size 784x24 clip at (10,202) size 780x20
+  RenderBlock {MARQUEE} at (0,24) size 784x24 [border: (2px solid #008000)]
+    RenderBlock {DIV} at (2,2) size 780x20
+      RenderInline {SPAN} at (0,0) size 91x19 [color=#FFFFFF]
+        RenderText {#text} at (0,0) size 91x19
+          text run at (0,0) width 91: "This is div two."