Store rotation/ui scale to local state.

ash/display/display_change_observer_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 "ash/display/display_change_observer_x11.h"
 
 #include <algorithm>
 #include <map>
 #include <set>
 #include <vector>
@@ skipping 178 matching lines @@
     int64 id = GetDisplayId(output, output_index);
 
     // If ID is invalid or there is an duplicate, just use output index.
     if (id == gfx::Display::kInvalidDisplayID || ids.find(id) != ids.end())
       id = output_index;
     ids.insert(id);
 
     displays.push_back(DisplayInfo(id, name, has_overscan));
     displays.back().set_device_scale_factor(device_scale_factor);
     displays.back().SetBounds(display_bounds);
+    // Invalidate ui_scale (and rotation) so that DisplayInfo::CopyFromNative
+    // ignores ui_scale and rotate value.
+    displays.back().set_ui_scale(0.0f);

[Jun Mukai, 2013/03/22 00:53:07]

setting a scale to '0' sounds awful to me. Why not 1.0f?

[oshima, 2013/03/22 02:06:51]

because 1.0f is valid scale. I understand that this may be confusing a bit. I
made it explicit flag.

   }
 
   // Free all allocated resources.
   for (std::map<XID, XRRCrtcInfo*>::const_iterator iter = crtc_info_map.begin();
        iter != crtc_info_map.end(); ++iter) {
     XRRFreeCrtcInfo(iter->second);
   }
   XRRFreeScreenResources(screen_resources);
 
   // DisplayManager can be null during the boot.
   Shell::GetInstance()->display_manager()->OnNativeDisplaysChanged(displays);
 }
 
 }  // namespace internal
 }  // namespace ash