Add context to gfx::Screen calls in support of simultaneous desktop+ash

chrome/browser/thumbnails/thumbnail_tab_helper.cc

Index: chrome/browser/thumbnails/thumbnail_tab_helper.cc
diff --git a/chrome/browser/thumbnails/thumbnail_tab_helper.cc b/chrome/browser/thumbnails/thumbnail_tab_helper.cc
index 69300bf490ce0e76cbd2730b6f924960b4f2de47..b6bc65883ef0fe2a9069e6d9cb2044ead01c5b5d 100644
--- a/chrome/browser/thumbnails/thumbnail_tab_helper.cc
+++ b/chrome/browser/thumbnails/thumbnail_tab_helper.cc
@@ -108,7 +108,8 @@ gfx::Size GetThumbnailSizeInPixel() {
   gfx::Size thumbnail_size(kThumbnailWidth, kThumbnailHeight);
   // Determine the resolution of the thumbnail based on the primary monitor.
   // TODO(oshima): Use device's default scale factor.
-  gfx::Display primary_display = gfx::Screen::GetPrimaryDisplay();
+  gfx::Display primary_display =
+      gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
   return gfx::ToFlooredSize(
       thumbnail_size.Scale(primary_display.device_scale_factor()));
 }