Allow upgrading to 2x DSF for lower UI scale when 2x resoruces are available.

ash/display/display_manager.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/display/display_manager.h"
 
 #include <cmath>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "ash/ash_switches.h"
 #include "ash/display/display_layout_store.h"
 #include "ash/display/screen_ash.h"
 #include "ash/screen_util.h"
 #include "ash/shell.h"
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "grit/ash_strings.h"
 #include "ui/base/l10n/l10n_util.h"
+#include "ui/base/layout.h"
+#include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/display.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/screen.h"
 #include "ui/gfx/size_conversions.h"
 
 #if defined(USE_X11)
 #include "ui/base/x/x11_util.h"
 #endif
 
 #if defined(OS_CHROMEOS)
@@ skipping 113 matching lines @@
       layout_store_(new DisplayLayoutStore),
       first_display_id_(gfx::Display::kInvalidDisplayID),
       num_connected_displays_(0),
       force_bounds_changed_(false),
       change_display_upon_host_resize_(false),
       second_display_mode_(EXTENDED),
       mirrored_display_id_(gfx::Display::kInvalidDisplayID) {
 #if defined(OS_CHROMEOS)
   change_display_upon_host_resize_ = !base::SysInfo::IsRunningOnChromeOS();
 #endif
+  DisplayInfo::SetAllowUpgradeToHighDPI(
+      ui::ResourceBundle::GetSharedInstance().GetMaxScaleFactor() ==
+      ui::SCALE_FACTOR_200P);
+
   gfx::Screen::SetScreenInstance(gfx::SCREEN_TYPE_ALTERNATE,
                                  screen_ash_.get());
   gfx::Screen* current_native =
       gfx::Screen::GetScreenByType(gfx::SCREEN_TYPE_NATIVE);
   // If there is no native, or the native was for shutdown,
   // use ash's screen.
   if (!current_native ||
       current_native == screen_for_shutdown) {
     gfx::Screen::SetScreenInstance(gfx::SCREEN_TYPE_NATIVE,
                                    screen_ash_.get());
@@ skipping 840 matching lines @@
   }
 #endif
 }
 
 gfx::Display DisplayManager::CreateDisplayFromDisplayInfoById(int64 id) {
   DCHECK(display_info_.find(id) != display_info_.end());
   const DisplayInfo& display_info = display_info_[id];
 
   gfx::Display new_display(display_info.id());
   gfx::Rect bounds_in_native(display_info.size_in_pixel());
-  float device_scale_factor = display_info.device_scale_factor();
-  if (device_scale_factor == 2.0f && display_info.configured_ui_scale() == 2.0f)
-    device_scale_factor = 1.0f;
+  float device_scale_factor = display_info.GetEffectiveDeviceScaleFactor();
 
   // Simply set the origin to (0,0).  The primary display's origin is
   // always (0,0) and the secondary display's bounds will be updated
   // in |UpdateSecondaryDisplayBoundsForLayout| called in |UpdateDisplay|.
   new_display.SetScaleAndBounds(
       device_scale_factor, gfx::Rect(bounds_in_native.size()));
   new_display.set_rotation(display_info.rotation());
   new_display.set_touch_support(display_info.touch_support());
   return new_display;
 }
@@ skipping 78 matching lines @@
       new_secondary_origin.Offset(-secondary_bounds.width(), offset);
       break;
   }
   gfx::Insets insets = secondary_display->GetWorkAreaInsets();
   secondary_display->set_bounds(
       gfx::Rect(new_secondary_origin, secondary_bounds.size()));
   secondary_display->UpdateWorkAreaFromInsets(insets);
 }
 
 }  // namespace ash