Gets button_dropdown compiling on linux.

views/controls/button/button_dropdown.cc

 // Copyright (c) 2006-2008 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 "views/controls/button/button_dropdown.h"
 
 #include "app/l10n_util.h"
 #include "base/compiler_specific.h"
 #include "base/message_loop.h"
 #include "grit/app_strings.h"
@@ skipping 63 matching lines @@
     SetState(BS_PUSHED);
     PaintNow();
     ShowDropDownMenu(GetWidget()->GetNativeView());
   }
 }
 
 bool ButtonDropDown::OnMouseDragged(const MouseEvent& e) {
   bool result = ImageButton::OnMouseDragged(e);
 
   if (!show_menu_factory_.empty()) {
-    // SM_CYDRAG is a pixel value for minimum dragging distance before operation
-    // counts as a drag, and not just as a click and accidental move of a mouse.
-    // See http://msdn2.microsoft.com/en-us/library/ms724385.aspx for details.
-    int dragging_threshold = GetSystemMetrics(SM_CYDRAG);
-
     // If the mouse is dragged to a y position lower than where it was when
     // clicked then we should not wait for the menu to appear but show
     // it immediately.
-    if (e.y() > y_position_on_lbuttondown_ + dragging_threshold) {
+    if (e.y() > y_position_on_lbuttondown_ + GetHorizontalDragThreshold()) {
       show_menu_factory_.RevokeAll();
       ShowDropDownMenu(GetWidget()->GetNativeView());
     }
   }
 
   return result;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 //
@@ skipping 23 matching lines @@
     menu_position.Offset(0, lb.height() - 1);
     if (UILayoutIsRightToLeft())
       menu_position.Offset(lb.width() - 1, 0);
 
     Menu::AnchorPoint anchor = Menu::TOPLEFT;
     if (UILayoutIsRightToLeft())
       anchor = Menu::TOPRIGHT;
 
     View::ConvertPointToScreen(this, &menu_position);
 
+#if defined(OS_WIN)
     int left_bound = GetSystemMetrics(SM_XVIRTUALSCREEN);
+#else
+    int left_bound = 0;
+    NOTIMPLEMENTED();
+#endif
     if (menu_position.x() < left_bound)
       menu_position.set_x(left_bound);
 
     scoped_ptr<Menu> menu(Menu::Create(menu_delegate_, anchor, window));
 
     // ID's for AppendMenu is 1-based because RunMenu will ignore the user
     // selection if id=0 is selected (0 = NO-OP) so we add 1 here and subtract 1
     // in the handlers above to get the actual index
     int item_count = menu_delegate_->GetItemCount();
     for (int i = 0; i < item_count; i++) {
@@ skipping 37 matching lines @@
 }
 
 bool ButtonDropDown::GetAccessibleState(AccessibilityTypes::State* state) {
   DCHECK(state);
 
   *state = AccessibilityTypes::STATE_HASPOPUP;
   return true;
 }
 
 }  // namespace views