Context menus should appear above the touch point if invoked by long press.

ui/views/controls/menu/menu_controller.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/controls/menu/menu_controller.h"
 
 #include "base/i18n/case_conversion.h"
 #include "base/i18n/rtl.h"
 #include "base/run_loop.h"
 #include "base/time.h"
@@ skipping 1546 matching lines @@
     // Offsets for context menu prevent menu items being selected by
     // simply opening the menu (bug 142992).
     if (MenuConfig::instance().offset_context_menus && state_.context_menu)
       x += 1;
 
     y = state_.initial_bounds.bottom();
     if (state_.anchor == MenuItemView::TOPRIGHT) {
       x = x + state_.initial_bounds.width() - pref.width();
       if (MenuConfig::instance().offset_context_menus && state_.context_menu)
         x -= 1;
+    } else if (state_.anchor == MenuItemView::BOTTOMCENTER) {
+      x = x - (pref.width() - state_.initial_bounds.width()) / 2;
+      y = std::max(0, state_.initial_bounds.y() - pref.height());
     }
 
     if (!state_.monitor_bounds.IsEmpty() &&
         y + pref.height() > state_.monitor_bounds.bottom()) {
       // The menu doesn't fit fully below the button on the screen. The menu
       // position with respect to the bounds will be preserved if it has
       // already been drawn. When the requested positioning is below the bounds
       // it will shrink the menu to make it fit below.
       // If the requested positioning is best fit, it will first try to fit the
       // menu below. If that does not fit it will try to place it above. If
@@ skipping 542 matching lines @@
 
 #if defined(USE_AURA)
 void MenuController::OnWindowActivated(aura::Window* active,
                                        aura::Window* old_active) {
   if (!drag_in_progress_)
     Cancel(EXIT_ALL);
 }
 #endif
 
 }  // namespace views