Make ViewRoot the top of the ViewAndroid tree

ui/display/test/test_screen.h

Index: ui/display/test/test_screen.h
diff --git a/ui/display/test/test_screen.h b/ui/display/test/test_screen.h
index 5672e7d0ae1dd76003d7a328bbefbd1bc83c1dde..3707b56e76d163c4bb488508f9195530beaaf5ed 100644
--- a/ui/display/test/test_screen.h
+++ b/ui/display/test/test_screen.h
@@ -30,6 +30,10 @@ class TestScreen : public ScreenBase {
   bool IsWindowUnderCursor(gfx::NativeWindow window) override;
   gfx::NativeWindow GetWindowAtScreenPoint(const gfx::Point& point) override;
   Display GetDisplayNearestWindow(gfx::NativeView view) const override;
+#if defined(OS_ANDROID)
+  Display GetDisplayNearestWindowAndroid(
+      gfx::NativeWindow window) const override;
+#endif
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TestScreen);