Context menu on views must show on mouse down for non-WIN.

ui/views/view.h

 // 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.
 
 #ifndef UI_VIEWS_VIEW_H_
 #define UI_VIEWS_VIEW_H_
 
 #include <algorithm>
 #include <map>
 #include <set>
@@ skipping 773 matching lines @@
   }
 
   // Provides default implementation for context menu handling. The default
   // implementation calls the ShowContextMenu of the current
   // ContextMenuController (if it is not NULL). Overridden in subclassed views
   // to provide right-click menu display triggerd by the keyboard (i.e. for the
   // Chrome toolbar Back and Forward buttons). No source needs to be specified,
   // as it is always equal to the current View.
   virtual void ShowContextMenu(const gfx::Point& p, bool is_mouse_gesture);
 
+  // On some platforms, we show context menu on mouse press instead of release.
+  // This method returns true for those platforms.
+  static bool ShouldShowContextMenuOnMousePress();
+
   // Drag and drop -------------------------------------------------------------
 
   DragController* drag_controller() { return drag_controller_; }
   void set_drag_controller(DragController* drag_controller) {
     drag_controller_ = drag_controller;
   }
 
   // During a drag and drop session when the mouse moves the view under the
   // mouse is queried for the drop types it supports by way of the
   // GetDropFormats methods. If the view returns true and the drag site can
@@ skipping 691 matching lines @@
   // Belongs to this view, but it's reference-counted on some platforms
   // so we can't use a scoped_ptr. It's dereferenced in the destructor.
   NativeViewAccessibility* native_view_accessibility_;
 
   DISALLOW_COPY_AND_ASSIGN(View);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_VIEW_H_