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

chrome/browser/tab_contents/thumbnail_generator.cc

Index: chrome/browser/tab_contents/thumbnail_generator.cc
diff --git a/chrome/browser/tab_contents/thumbnail_generator.cc b/chrome/browser/tab_contents/thumbnail_generator.cc
index 09ce31ac785b45f036c4a5c25e822216b662a5bf..5f20bea2f944b0b751b61e091010348531cf5b42 100644
--- a/chrome/browser/tab_contents/thumbnail_generator.cc
+++ b/chrome/browser/tab_contents/thumbnail_generator.cc
@@ -128,7 +128,8 @@ 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());
 }