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

ash/wm/window_resizer.cc

Index: ash/wm/window_resizer.cc
diff --git a/ash/wm/window_resizer.cc b/ash/wm/window_resizer.cc
index c759c9162ab84bda43fb1a4c3f6afacfd7e38ac7..900dedbebd8e3dd1f033f10b0c83c75e7bbbeb0b 100644
--- a/ash/wm/window_resizer.cc
+++ b/ash/wm/window_resizer.cc
@@ -271,8 +271,8 @@ int WindowResizer::GetWidthForDrag(const Details& details,
     }
 
     // And don't let the window go bigger than the display.
-    int max_width =
-        gfx::Screen::GetDisplayNearestWindow(details.window).bounds().width();
+    int max_width = Shell::GetAshScreen()->GetDisplayNearestWindow(
+        details.window).bounds().width();
     if (width > max_width) {
       width = max_width;
       *delta_x = -x_multiplier * (details.initial_bounds.width() - max_width);
@@ -299,8 +299,8 @@ int WindowResizer::GetHeightForDrag(const Details& details,
     }
 
     // And don't let the window go bigger than the display.
-    int max_height =
-        gfx::Screen::GetDisplayNearestWindow(details.window).bounds().height();
+    int max_height = Shell::GetAshScreen()->GetDisplayNearestWindow(
+        details.window).bounds().height();
     if (height > max_height) {
       height = max_height;
       *delta_y = -y_multiplier * (details.initial_bounds.height() - max_height);