ozone: drm: Fix RejectBufferWithIncompatibleModifiers and disable it

This test is broken - it's trying to verify that non-matching modifiers
will cause screen manager to reject the current buffer for modesetting,
but currently we do accept the buffer. The only reason the test passes is
because the EXPECT_NE() checks that the framebuffer id doesn't match the
current framebuffer, when it should check the opaque framebuffer id.

Bug: 868010

Change-Id: I1f2312e6bc698f68f3806afd79ac07c19c3027cb
Reviewed-on: https://chromium-review.googlesource.com/1155914
Commit-Queue: Michael Spang <spang@chromium.org>
Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579573}

ui/ozone/platform/drm/gpu/screen_manager_unittest.cc

@@ -524,7 +524,8 @@ TEST_F(ScreenManagerTest, EnableControllerWhenWindowHasBuffer) {
   window->Shutdown();
 }
 
-TEST_F(ScreenManagerTest, RejectBufferWithIncompatibleModifiers) {
+// See crbug.com/868010
+TEST_F(ScreenManagerTest, DISABLED_RejectBufferWithIncompatibleModifiers) {
   std::unique_ptr<ui::DrmWindow> window(
       new ui::DrmWindow(1, device_manager_.get(), screen_manager_.get()));
   window->Initialize(buffer_generator_.get());
@@ -550,6 +551,7 @@ TEST_F(ScreenManagerTest, RejectBufferWithIncompatibleModifiers) {
   // I915_FORMAT_MOD_X_TILED modifier we created above and the two
   // framebuffer IDs should be different.
   EXPECT_NE(buffer->GetFramebufferId(), drm_->current_framebuffer());
+  EXPECT_NE(buffer->GetOpaqueFramebufferId(), drm_->current_framebuffer());
 
   window = screen_manager_->RemoveWindow(1);
   window->Shutdown();