Remember the configured device scale factor for external displays.

ash/display/display_info.cc

 // Copyright (c) 2013 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 <stdio.h>
 #include <string>
 #include <vector>
 
 #include "ash/display/display_info.h"
 #include "base/logging.h"
@@ skipping 110 matching lines @@
           case 'l':  // rotate 90 degrees to 'left'.
             rotation = gfx::Display::ROTATE_270;
             break;
         }
       }
     }
   }
 
   int x = 0, y = 0, width, height;
   float device_scale_factor = 1.0f;
   if (sscanf(main_spec.c_str(), "%dx%d*%f",

[oshima, 2014/08/07 23:03:49]

can you consolidate this?

[Jun Mukai, 2014/08/08 00:57:33]

Done.

              &width, &height, &device_scale_factor) >= 2 ||
       sscanf(main_spec.c_str(), "%d+%d-%dx%d*%f", &x, &y, &width, &height,
              &device_scale_factor) >= 4) {
     bounds_in_native.SetRect(x, y, width, height);
   } else {
 #if defined(OS_WIN)
     if (gfx::IsHighDPIEnabled()) {
       device_scale_factor = gfx::GetDPIScale();
     }
 #endif
   }
 
   std::vector<DisplayMode> display_modes;
   if (Tokenize(main_spec, "#", &parts) == 2) {
     size_t native_mode = 0;
     int largest_area = -1;
     float highest_refresh_rate = -1.0f;
     main_spec = parts[0];
     std::string resolution_list = parts[1];
     count = Tokenize(resolution_list, "|", &parts);
     for (size_t i = 0; i < count; ++i) {
       std::string resolution = parts[i];
       int width, height;
       float refresh_rate = 0.0f;
+      float device_scale_factor = 1.0f;
+      size_t asterisk_pos = resolution.find("*");
+      if (asterisk_pos != std::string::npos) {
+        sscanf(resolution.substr(asterisk_pos + 1).c_str(),
+               "%f",
+               &device_scale_factor);
+        resolution = resolution.substr(0, asterisk_pos);
+      }
       if (sscanf(resolution.c_str(),
                  "%dx%d%%%f",
                  &width,
                  &height,
                  &refresh_rate) >= 2) {
         if (width * height >= largest_area &&
             refresh_rate > highest_refresh_rate) {
           // Use mode with largest area and highest refresh rate as native.
           largest_area = width * height;
           highest_refresh_rate = refresh_rate;
           native_mode = i;
         }
-        display_modes.push_back(
-            DisplayMode(gfx::Size(width, height), refresh_rate, false, false));
+        DisplayMode mode(gfx::Size(width, height), refresh_rate, false, false);
+        mode.device_scale_factor = device_scale_factor;
+        display_modes.push_back(mode);
       }
     }
     display_modes[native_mode].native = true;
   }
 
   if (id == gfx::Display::kInvalidDisplayID)
     id = synthesized_display_id++;
   DisplayInfo display_info(
       id, base::StringPrintf("Display-%d", static_cast<int>(id)), has_overscan);
   display_info.set_device_scale_factor(device_scale_factor);
@@ skipping 180 matching lines @@
 }
 
 bool DisplayInfo::IsColorProfileAvailable(
     ui::ColorCalibrationProfile profile) const {
   return std::find(available_color_profiles_.begin(),
                    available_color_profiles_.end(),
                    profile) != available_color_profiles_.end();
 }
 
 }  // namespace ash