Ruby: Update beforeChild when redirecting renderer insertion to a child.

Source/core/rendering/RenderRuby.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 147 matching lines @@
     }
 
     // If the child is a ruby run, just add it normally.
     if (child->isRubyRun()) {
         RenderInline::addChild(child, beforeChild);
         return;
     }
 
     if (beforeChild && !isAfterContent(beforeChild)) {
         // insert child into run
-        ASSERT(!beforeChild->isRubyRun());
         RenderObject* run = beforeChild;
         while (run && !run->isRubyRun())
             run = run->parent();
         if (run) {
+            if (beforeChild == run)
+                beforeChild = toRenderRubyRun(beforeChild)->firstChild();
+            ASSERT(!beforeChild || beforeChild->isDescendantOf(run));
             run->addChild(child, beforeChild);
             return;
         }
         ASSERT_NOT_REACHED(); // beforeChild should always have a run as parent!
         // Emergency fallback: fall through and just append.
     }
 
     // If the new child would be appended, try to add the child to the previous run
     // if possible, or create a new run otherwise.
     // (The RenderRubyRun object will handle the details)
@@ skipping 81 matching lines @@
     }
 
     // If the child is a ruby run, just add it normally.
     if (child->isRubyRun()) {
         RenderBlockFlow::addChild(child, beforeChild);
         return;
     }
 
     if (beforeChild && !isAfterContent(beforeChild)) {
         // insert child into run
-        ASSERT(!beforeChild->isRubyRun());
         RenderObject* run = beforeChild;
         while (run && !run->isRubyRun())
             run = run->parent();
         if (run) {
+            if (beforeChild == run)
+                beforeChild = toRenderRubyRun(beforeChild)->firstChild();
+            ASSERT(!beforeChild || beforeChild->isDescendantOf(run));
             run->addChild(child, beforeChild);
             return;
         }
         ASSERT_NOT_REACHED(); // beforeChild should always have a run as parent!
         // Emergency fallback: fall through and just append.
     }
 
     // If the new child would be appended, try to add the child to the previous run
     // if possible, or create a new run otherwise.
     // (The RenderRubyRun object will handle the details)
@@ skipping 23 matching lines @@
         return;
     }
 
     // Otherwise find the containing run and remove it from there.
     RenderRubyRun* run = findRubyRunParent(child);
     ASSERT(run);
     run->removeChild(child);
 }
 
 } // namespace blink