A couple of fixes to bubble view:

ui/views/bubble/bubble_frame_view.cc

 // Copyright (c) 2012 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/views/bubble/bubble_frame_view.h"
 
 #include <algorithm>
 
 #include "grit/ui_resources.h"
 #include "ui/base/hit_test.h"
@@ skipping 166 matching lines @@
   // Give the contents a margin.
   client_size.Enlarge(content_margins_.width(), content_margins_.height());
 
   const BubbleBorder::ArrowLocation arrow = bubble_border_->arrow_location();
   if (adjust_if_offscreen && BubbleBorder::has_arrow(arrow)) {
     if (!bubble_border_->is_arrow_at_center(arrow)) {
       // Try to mirror the anchoring if the bubble does not fit on the screen.
       MirrorArrowIfOffScreen(true, anchor_rect, client_size);
       MirrorArrowIfOffScreen(false, anchor_rect, client_size);
     } else {
+      MirrorArrowIfOffScreen(BubbleBorder::is_arrow_on_horizontal(arrow),

[msw, 2013/03/14 20:17:58]

nit: Add a minor comment like "Mirror as needed vertically if the arrow is on a
horizontal edge and vice-versa."

[varunjain, 2013/03/14 20:54:59]

Done.

+          anchor_rect, client_size);
       OffsetArrowIfOffScreen(anchor_rect, client_size);
     }
   }
 
   // Calculate the bounds with the arrow in its updated location and offset.
   return bubble_border_->GetBounds(anchor_rect, client_size);
 }
 
 gfx::Rect BubbleFrameView::GetMonitorBounds(const gfx::Rect& rect) {
   // TODO(scottmg): Native is wrong. http://crbug.com/133312
@@ skipping 57 matching lines @@
   // |offscreen_adjust|, e.g. positive |offscreen_adjust| means bubble
   // window needs to be moved to the right and that means we need to move arrow
   // to the left, and that means negative offset.
   bubble_border_->set_arrow_offset(
       bubble_border_->GetArrowOffset(window_bounds.size()) - offscreen_adjust);
   if (offscreen_adjust)
     SchedulePaint();
 }
 
 }  // namespace views