X11 and Ozone: cleanup views_unittests

There are some USE_X11 guards that I needed to fix.

-----

PS: Please note that this is a temp solution that will help to choose
between ozone and non-ozone X11 build. The switch that will be used
to choose the path is --enable-features=UseOzonePlatform. Once
non-Ozone X11 path is removed (hopefully by Q1 2021 depending on how
the finch trial goes), the wrapper will be removed.

Please also note that it's impossible to build use_x11 && use_ozone
without some hacks in PlatformCursor code. The changes to that are
on their way to upstream.

----

Bug: 1085700
Change-Id: I5562751867d876b0cbf6a4bde7e71daf2395d541
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2333842Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Maksim Sisov (GMT+3) <msisov@igalia.com>
Cr-Commit-Position: refs/heads/master@{#794877}

ui/base/x/BUILD.gn

@@ -74,6 +74,7 @@ jumbo_component("x") {
     "//net",
     "//skia",
     "//ui/base:data_exchange",
+    "//ui/base:features",
     "//ui/base:hit_test",
     "//ui/base:wm_role_names",
     "//ui/base/clipboard:clipboard_types",

ui/base/x/x11_window.cc

@@ -17,6 +17,7 @@
 #include "net/base/network_interfaces.h"
 #include "third_party/skia/include/core/SkRegion.h"
 #include "ui/base/hit_test_x11.h"
+#include "ui/base/ui_base_features.h"
 #include "ui/base/wm_role_names_linux.h"
 #include "ui/base/x/x11_menu_registrar.h"
 #include "ui/base/x/x11_pointer_grab.h"
@@ -216,7 +217,6 @@ void XWindow::Init(const Configuration& config) {
   if (!activatable_ || config.override_redirect)
     req.override_redirect = x11::Bool32(true);
 
-#if !defined(USE_X11)
   // It seems like there is a difference how tests are instantiated in case of
   // non-Ozone X11 and Ozone. See more details in
   // EnableTestConfigForPlatformWindows. The reason why this must be here is
@@ -227,9 +227,8 @@ void XWindow::Init(const Configuration& config) {
   // PlatformWindow, and non-Ozone X11 uses it, we have to add this workaround
   // here. Otherwise, tests for non-Ozone X11 fail.
   // TODO(msisov): figure out usage of this for non-Ozone X11.
-  if (UseTestConfigForPlatformWindows())
+  if (features::IsUsingOzonePlatform() && UseTestConfigForPlatformWindows())
     req.override_redirect = x11::Bool32(true);
-#endif
 
   override_redirect_ = req.override_redirect.has_value();
 

ui/views/widget/desktop_aura/desktop_drag_drop_client_ozone.cc

@@ -22,6 +22,7 @@
 #include "ui/base/dragdrop/drag_drop_types.h"
 #include "ui/base/dragdrop/drop_target_event.h"
 #include "ui/base/layout.h"
+#include "ui/base/ui_base_features.h"
 #include "ui/display/screen.h"
 #include "ui/ozone/public/ozone_platform.h"
 #include "ui/platform_window/platform_window_delegate.h"
@@ -45,14 +46,13 @@ constexpr uint32_t kMinAlpha = 32;
 
 bool DragImageIsNeeded() {
 #if defined(USE_OZONE)
-  return !ui::OzonePlatform::GetInstance()
-              ->GetPlatformProperties()
-              .platform_shows_drag_image;
-#elif defined(USE_X11)
-  return true;
-#else
-#error "This file must not be compiled out of Ozone or X11."
+  if (features::IsUsingOzonePlatform()) {
+    return !ui::OzonePlatform::GetInstance()
+                ->GetPlatformProperties()
+                .platform_shows_drag_image;
+  }
 #endif
+  return true;
 }
 
 // Returns true if |image| has any visible regions (defined as having a pixel