mus: Implement interwindow drag and drop

services/ui/ws/test_utils.cc

Index: services/ui/ws/test_utils.cc
diff --git a/services/ui/ws/test_utils.cc b/services/ui/ws/test_utils.cc
index b9ef94cf25b48b22c0dfabc569c912e1866f6735..3f19d78e679512359bc64c7c3095ae20b344d018 100644
--- a/services/ui/ws/test_utils.cc
+++ b/services/ui/ws/test_utils.cc
@@ -349,6 +349,26 @@ void TestWindowTreeClient::OnWindowPredefinedCursorChanged(
   tracker_.OnWindowPredefinedCursorChanged(window_id, cursor_id);
 }
 
+void TestWindowTreeClient::OnDragEnter(
+    uint32_t window,
+    mojo::Map<mojo::String, mojo::Array<uint8_t>> drag_data,
+    uint32_t key_state,
+    const gfx::Point& position,
+    uint32_t effect_bitmask,
+    const OnDragEnterCallback& callback) {}
+
+void TestWindowTreeClient::OnDragOver(uint32_t window,
+                                      uint32_t key_state,
+                                      const gfx::Point& position,
+                                      uint32_t effect_bitmask,
+                                      const OnDragOverCallback& callback) {}
+void TestWindowTreeClient::OnDragLeave(uint32_t window) {}
+void TestWindowTreeClient::OnDragDrop(uint32_t window,
+                                      uint32_t key_state,
+                                      const gfx::Point& position,
+                                      uint32_t effect_bitmask,
+                                      const OnDragDropCallback& callback) {}
+
 void TestWindowTreeClient::OnChangeCompleted(uint32_t change_id, bool success) {
   if (record_on_change_completed_)
     tracker_.OnChangeCompleted(change_id, success);