Revert of views: Initialize DesktopScreenX11::primary_display_index_.

ui/views/widget/desktop_aura/desktop_screen_x11.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/widget/desktop_aura/desktop_screen_x11.h"
 
 #include <X11/extensions/Xrandr.h>
 #include <X11/Xlib.h>
 
 // It clashes with out RootWindow.
@@ skipping 268 matching lines @@
 ////////////////////////////////////////////////////////////////////////////////
 // DesktopScreenX11, private:
 
 DesktopScreenX11::DesktopScreenX11(
     const std::vector<display::Display>& test_displays)
     : xdisplay_(gfx::GetXDisplay()),
       x_root_window_(DefaultRootWindow(xdisplay_)),
       has_xrandr_(false),
       xrandr_event_base_(0),
       displays_(test_displays),
-      primary_display_index_(0),
       atom_cache_(xdisplay_, kAtomsToCache) {}
 
 std::vector<display::Display> DesktopScreenX11::BuildDisplaysFromXRandRInfo() {
   std::vector<display::Display> displays;
   gfx::XScopedPtr<
       XRRScreenResources,
       gfx::XObjectDeleter<XRRScreenResources, void, XRRFreeScreenResources>>
       resources(XRRGetScreenResourcesCurrent(xdisplay_, x_root_window_));
   if (!resources) {
     LOG(ERROR) << "XRandR returned no displays. Falling back to Root Window.";
@@ skipping 98 matching lines @@
       GetPrimaryDisplay().device_scale_factor());
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
 display::Screen* CreateDesktopScreen() {
   return new DesktopScreenX11;
 }
 
 }  // namespace views