Start of display management for mus

components/mus/ws/window_tree_unittest.cc

Index: components/mus/ws/window_tree_unittest.cc
diff --git a/components/mus/ws/window_tree_unittest.cc b/components/mus/ws/window_tree_unittest.cc
index 1a8f84b00bb41a25df14e0d77fdb386a084a095f..d985e6e5f2c8bcd8615d6e03762d74ba5fc5cca4 100644
--- a/components/mus/ws/window_tree_unittest.cc
+++ b/components/mus/ws/window_tree_unittest.cc
@@ -312,6 +312,7 @@ class TestDisplayManager : public DisplayManager {
   void SetViewportSize(const gfx::Size& size) override {}
   void SetTitle(const base::string16& title) override {}
   void SetCursorById(int32_t cursor) override { *cursor_id_storage_ = cursor; }
+  mojom::Rotation GetRotation() override { return mojom::Rotation::VALUE_0; }
   const mojom::ViewportMetrics& GetViewportMetrics() override {
     return display_metrices_;
   }