Display anonymous regions in DRT

LayoutTests/platform/win/fast/repaint/japanese-rl-selection-repaint-in-regions-expected.txt

 layer at (0,0) size 800x600
   RenderView at (0,0) size 800x600
 layer at (754,0) size 46x600
   RenderBlock {HTML} at (0,0) size 46x600 [border: (10px solid #800000)]
     RenderBody {BODY} at (18,18) size 10x564 [border: (5px solid #000000)]
 layer at (296,100) size 404x404
-  RenderRegion {DIV} at (100,100) size 404x404 [border: (2px solid #000000)]
-Flow Threads
-  Thread with flow-name 'thread'
+  RenderBlock (positioned) {DIV} at (100,100) size 404x404 [border: (2px solid #000000)]
+    RenderNamedFlowFragment at (2,2) size 400x400
+Named flows
+  Named flow 'thread'
     layer at (400,0) size 400x400
       RenderNamedFlowThread at (0,0) size 400x400
         RenderBlock {DIV} at (0,0) size 325x400
           RenderText {#text} at (1,0) size 322x400
             text run at (1,0) width 387: "\x{305B}\x{3063}\x{304B}\x{304F}\x{898B}\x{3064}\x{3051}\x{305F}\x{3059}\x{3070}\x{3089}\x{3057}\x{3044}\x{8A18}\x{4E8B}\x{304C}\x{3069}\x{3053}\x{306B}\x{3042}\x{3063}"
             text run at (26,0) width 384: "\x{305F}\x{304B}\x{5FD8}\x{308C}\x{3066}\x{3057}\x{307E}\x{3063}\x{305F}\x{7D4C}\x{9A13}\x{306F}\x{3042}\x{308A}\x{307E}\x{3059}\x{304B}\x{306A}\x{3089}\x{30BF}"
             text run at (51,0) width 388: "\x{30A4}\x{30C8}\x{30EB}\x{3068}\x{30A2}\x{30C9}\x{30EC}\x{30B9}\x{3060}\x{3051}\x{3067}\x{306A}\x{304F}\x{3001}\x{8A2A}\x{554F}\x{3057}\x{305F}\x{30A6}\x{30A7}\x{30D6}"
             text run at (76,0) width 387: "\x{30DA}\x{30FC}\x{30B8}\x{306E}\x{30B3}\x{30F3}\x{30C6}\x{30F3}\x{30C4}\x{304B}\x{3089}\x{3082}\x{691C}\x{7D22}\x{3059}\x{308B}\x{3053}\x{3068}\x{304C}\x{3067}\x{304D}"
             text run at (101,0) width 395: "\x{307E}\x{3059}\x{3002}\x{305B}\x{3063}\x{304B}\x{304F}\x{898B}\x{3064}\x{3051}\x{305F}\x{3059}\x{3070}\x{3089}\x{3057}\x{3044}\x{8A18}\x{4E8B}\x{304C}\x{3069}\x{3053}"
             text run at (126,0) width 377: "\x{306B}\x{3042}\x{3063}\x{305F}\x{304B}\x{5FD8}\x{308C}\x{3066}\x{3057}\x{307E}\x{3063}\x{305F}\x{7D4C}\x{9A13}\x{306F}\x{3042}\x{308A}\x{307E}\x{3059}\x{304B}"
             text run at (151,0) width 396: "\x{306A}\x{3089}\x{30BF}\x{30A4}\x{30C8}\x{30EB}\x{3068}\x{30A2}\x{30C9}\x{30EC}\x{30B9}\x{3060}\x{3051}\x{3067}\x{306A}\x{304F}\x{3001}\x{8A2A}\x{554F}\x{3057}\x{305F}"
             text run at (176,0) width 400: "\x{30A6}\x{30A7}\x{30D6}\x{30DA}\x{30FC}\x{30B8}\x{306E}\x{30B3}\x{30F3}\x{30C6}\x{30F3}\x{30C4}\x{304B}\x{3089}\x{3082}\x{691C}\x{7D22}\x{3059}\x{308B}\x{3053}\x{3068}\x{304C}"
             text run at (201,0) width 382: "\x{3067}\x{304D}\x{307E}\x{3059}\x{3002}\x{8A2A}\x{554F}\x{3057}\x{305F}\x{30A6}\x{30A7}\x{30D6}\x{30DA}\x{30FC}\x{30B8}\x{306E}\x{30B3}\x{30F3}\x{30C6}\x{30F3}\x{30C4}"
             text run at (226,0) width 399: "\x{304B}\x{3089}\x{3082}\x{691C}\x{7D22}\x{3059}\x{308B}\x{3053}\x{3068}\x{304C}\x{3067}\x{304D}\x{307E}\x{3059}\x{3002}\x{305B}\x{3063}\x{304B}\x{304F}\x{898B}\x{3064}"
             text run at (251,0) width 394: "\x{3051}\x{305F}\x{3059}\x{3070}\x{3089}\x{3057}\x{3044}\x{8A18}\x{4E8B}\x{304C}\x{3069}\x{3053}\x{306B}\x{3042}\x{3063}\x{305F}\x{304B}\x{5FD8}\x{308C}\x{3066}\x{3057}"
             text run at (276,0) width 385: "\x{307E}\x{3063}\x{305F}\x{7D4C}\x{9A13}\x{306F}\x{3042}\x{308A}\x{307E}\x{3059}\x{304B} \x{306A}\x{3089}\x{30BF}\x{30A4}\x{30C8}\x{30EB}\x{3068}\x{30A2}\x{30C9}"
             text run at (301,0) width 190: "\x{30EC}\x{30B9}\x{3060}\x{3051}\x{3067}\x{306A}\x{304F}\x{3001}\x{8A2A}\x{554F}"
-  Regions for flow 'thread'
-    RenderRegion {DIV}
+    Regions for named flow 'thread'
+      RenderNamedFlowFragment (anonymous child of {DIV})
 selection start: position 74 of child 0 {#text} of child 1 {DIV} of body
 selection end:   position 242 of child 0 {#text} of child 1 {DIV} of body