Fix ash_ui_perftests compile

Fix ash_ui_perftests compile after https://crrev.com/c/1775390

Bug: 973483
Change-Id: Iaebaa8ffe341080f01f28a5e399cd0a4ebf7e673
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1795488Reviewed-by: Matthew Mourgos <mmourgos@chromium.org>
Commit-Queue: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#695293}

ash/shell/content/test/ash_content_test.cc

@@ -6,6 +6,7 @@
 
 #include <utility>
 
+#include "ash/public/cpp/shelf_config.h"
 #include "ash/shell.h"
 #include "ash/shell/content/client/shell_browser_main_parts.h"
 #include "ash/shell/content/embedded_browser.h"
@@ -146,8 +147,8 @@ void AshContentTest::SetUpOnMainThread() {
         GetUMAHistogramNames());
   }
   gfx::Size display_size = ash::Shell::GetPrimaryRootWindow()->bounds().size();
-  test_window_size_.set_height((display_size.height() - ash::kShelfSize) *
-                               0.95f);
+  test_window_size_.set_height(
+      (display_size.height() - ash::ShelfConfig::Get()->shelf_size()) * 0.95f);
   test_window_size_.set_width(display_size.width() * 0.7f);
 }