Ensure the margin for uber tray popup arrow position.

ash/system/tray/system_tray_bubble.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 "ash/system/tray/system_tray_bubble.h"
 
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/system/tray/system_tray.h"
 #include "ash/system/tray/system_tray_delegate.h"
@@ skipping 192 matching lines @@
     canvas->FillRect(gfx::Rect(kLeftPadding, y, owner_->width(),
                                kBottomLineHeight), kBorderDarkColor);
 
     if (!Shell::GetInstance()->shelf()->IsVisible())
       return;
 
     // Draw the arrow.
     if (arrow_type_ == ARROW_TYPE_BOTTOM) {
       int tip_x = base::i18n::IsRTL() ? arrow_offset_ :
           owner_->width() - arrow_offset_;
+      if (tip_x < kArrowPaddingFromRight + kArrowWidth / 2)
+        tip_x = kArrowPaddingFromRight + kArrowWidth / 2;
+      if (tip_x > owner_->width() - kArrowPaddingFromRight - kArrowWidth / 2)
+        tip_x = owner_->width() - kArrowPaddingFromRight - kArrowWidth / 2;
       int left_base_x = tip_x - kArrowWidth / 2;
       int left_base_y = y;
       int tip_y = left_base_y + kArrowHeight;
 
       SkPath path;
       path.incReserve(4);
       path.moveTo(SkIntToScalar(left_base_x), SkIntToScalar(left_base_y));
       path.lineTo(SkIntToScalar(tip_x), SkIntToScalar(tip_y));
       path.lineTo(SkIntToScalar(left_base_x + kArrowWidth),
                   SkIntToScalar(left_base_y));
@@ skipping 280 matching lines @@
 }
 
 void SystemTrayBubble::OnWidgetClosing(views::Widget* widget) {
   CHECK_EQ(bubble_widget_, widget);
   bubble_widget_ = NULL;
   tray_->RemoveBubble(this);
 }
 
 }  // namespace internal
 }  // namespace ash