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 fc08f8db4f1a960492225fc6782b6fc8f6c935a9..73688b151a45e00a04a93f323ff0df79311cee44 100644
--- a/chrome/browser/thumbnails/thumbnail_tab_helper.cc
+++ b/chrome/browser/thumbnails/thumbnail_tab_helper.cc
@@ -107,7 +107,8 @@ 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 thumbnail_size.Scale(primary_display.device_scale_factor());
 }