[views-mus] Support custom cursors.

services/ui/public/interfaces/cursor/cursor_struct_traits_unittest.cc

Index: services/ui/public/interfaces/cursor/cursor_struct_traits_unittest.cc
diff --git a/services/ui/public/interfaces/cursor/cursor_struct_traits_unittest.cc b/services/ui/public/interfaces/cursor/cursor_struct_traits_unittest.cc
index db2c6c4754af3d0c50399d3739ec4787635bf8f4..011b4122f4495bbc7acb6f8a95d6a923a7a40e08 100644
--- a/services/ui/public/interfaces/cursor/cursor_struct_traits_unittest.cc
+++ b/services/ui/public/interfaces/cursor/cursor_struct_traits_unittest.cc
@@ -99,4 +99,21 @@ TEST_F(CursorStructTraitsTest, TestBitmapCursor) {
   }
 }
 
+// Test that we deal with empty bitmaps. (When a cursor resource isn't loaded
+// in the renderer, the renderer will send a kCurstomCursor with an empty
+// bitmap.)
+TEST_F(CursorStructTraitsTest, TestEmptyCursor) {
+  const base::TimeDelta kFrameDelay = base::TimeDelta::FromMilliseconds(15);
+  const gfx::Point kHotspot = gfx::Point(5, 2);
+  const float kScale = 2.0f;
+
+  ui::CursorData input(kHotspot, {SkBitmap()}, kScale, kFrameDelay);
+
+  ui::CursorData output;
+  ASSERT_TRUE(EchoCursorData(input, &output));

[sky, 2017/04/26 22:16:15]

optional: you don't need to route through mojom to test serialization. See
https://groups.google.com/a/chromium.org/forum/#!searchin/chromium-mojo/trait...
.

[Elliot Glaysher, 2017/04/26 23:09:04]

I'm confused. Isn't that what I'm doing here? This calls the
mojom::Deserialize(mojom::Serialize()) pattern wrapped in EchoCursorData().

[sky, 2017/04/26 23:35:01]

Indeed you are. I was confused by the name. Sorry.

+
+  ASSERT_EQ(1u, output.cursor_frames().size());
+  EXPECT_TRUE(output.cursor_frames().front().empty());
+}
+
 }  // namespace ui