fix incorrect bounds on remove child from root

ui/gfx/geometry/r_tree.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/geometry/r_tree.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/logging.h"
@@ skipping 714 matching lines @@
 
     child = parent;
     parent = parent->parent();
   }
 
   // If we stopped deleting nodes up the tree before encountering the root,
   // we'll need to fix up the bounds from the first parent we didn't delete
   // up to the root.
   if (parent) {
     parent->RecomputeBounds();
+  } else {
+    root_->RecomputeBounds();
   }
 
   // Now re-insert each of the orphaned nodes back into the tree.
   for (size_t i = 0; i < orphans.size(); ++i) {
     int starting_level = -1;
     InsertNode(orphans[i], &starting_level);
   }
 
   // Clear out the orphans list without deleting any of the children, as they
   // have been re-inserted into the tree.
   orphans.weak_clear();
 }
 
 }  // namespace gfx