Re-land: exo: Take blending into account when setting opaque property.

components/exo/surface_unittest.cc

Index: components/exo/surface_unittest.cc
diff --git a/components/exo/surface_unittest.cc b/components/exo/surface_unittest.cc
index 6c7ca96819c55eeafba52e841726ef75c13a6185..4ebc6bb142a985f6c1604d3a8555f4d0d153723f 100644
--- a/components/exo/surface_unittest.cc
+++ b/components/exo/surface_unittest.cc
@@ -206,8 +206,6 @@ TEST_F(SurfaceTest, SetBlendMode) {
   surface->SetBlendMode(SkXfermode::kSrc_Mode);
   surface->Commit();
 
-  EXPECT_FALSE(surface->window()->layer()->fills_bounds_opaquely());
-
   const cc::DelegatedFrameData* frame_data = GetFrameFromSurface(surface.get());
   ASSERT_EQ(1u, frame_data->render_pass_list.size());
   ASSERT_EQ(1u, frame_data->render_pass_list.back()->quad_list.size());