Ignore UI scaling when internal display isn't active (in docked mode, for example)

ash/display/display_util.cc

 // Copyright 2014 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_util.h"
 
 #include <algorithm>
 
 #include "ash/display/display_info.h"
 #include "ash/display/display_manager.h"
@@ skipping 155 matching lines @@
                  << resolution.ToString();
     return false;
   }
   *out = *iter;
   return true;
 }
 
 bool GetDisplayModeForNextUIScale(const DisplayInfo& info,
                                   bool up,
                                   DisplayMode* out) {
-  if (!gfx::Display::IsInternalDisplayId(info.id()))
+  DisplayManager* display_manager = Shell::GetInstance()->display_manager();
+  if (!display_manager->IsActiveDisplayId(info.id()) ||
+      !gfx::Display::IsInternalDisplayId(info.id())) {
     return false;
+  }
   const std::vector<DisplayMode>& modes = info.display_modes();
   ScaleComparator comparator(info.configured_ui_scale());
   auto iter = std::find_if(modes.begin(), modes.end(), comparator);
   FindNextMode(iter, modes, up, out);
   return true;
 }
 
 bool GetDisplayModeForNextResolution(const DisplayInfo& info,
                                      bool up,
                                      DisplayMode* out) {
   if (gfx::Display::IsInternalDisplayId(info.id()))
     return false;
   const std::vector<DisplayMode>& modes = info.display_modes();
   DisplayMode tmp(info.size_in_pixel(), 0.0f, false, false);
   tmp.device_scale_factor = info.device_scale_factor();
   gfx::Size resolution = tmp.GetSizeInDIP(false);
   auto iter = std::find_if(modes.begin(), modes.end(),
                            [resolution](const DisplayMode& mode) {
                              return mode.GetSizeInDIP(false) == resolution;
                            });
   FindNextMode(iter, modes, up, out);
   return true;
 }
 
 bool SetDisplayUIScale(int64 id, float ui_scale) {
   DisplayManager* display_manager = Shell::GetInstance()->display_manager();
+  if (!display_manager->IsActiveDisplayId(id) ||
+      !gfx::Display::IsInternalDisplayId(id)) {
+    return false;
+  }
   const DisplayInfo& info = display_manager->GetDisplayInfo(id);
   DisplayMode mode;
   if (!GetDisplayModeForUIScale(info, ui_scale, &mode))
     return false;
   return display_manager->SetDisplayMode(id, mode);
 }
 
 bool HasDisplayModeForUIScale(const DisplayInfo& info, float ui_scale) {
   ScaleComparator comparator(ui_scale);
   const std::vector<DisplayMode>& modes = info.display_modes();
@@ skipping 137 matching lines @@
   // Output index is stored in the first 8 bits. See GetDisplayIdFromEDID
   // in edid_parser.cc.
   int index_1 = id1 & 0xFF;
   int index_2 = id2 & 0xFF;
   DCHECK_NE(index_1, index_2) << id1 << " and " << id2;
   return gfx::Display::IsInternalDisplayId(id1) ||
          (index_1 < index_2 && !gfx::Display::IsInternalDisplayId(id2));
 }
 
 }  // namespace ash