chromeos: changes how DisplayManagerObservers are notified

services/ui/ws/test_utils.h

Index: services/ui/ws/test_utils.h
diff --git a/services/ui/ws/test_utils.h b/services/ui/ws/test_utils.h
index b5a9886d49b5afeea96ffad4d576f2c728e8f16c..da87cc8d749f5b318c8998ca915dd5f2c225be10 100644
--- a/services/ui/ws/test_utils.h
+++ b/services/ui/ws/test_utils.h
@@ -597,6 +597,8 @@ class TestWindowServerDelegate : public WindowServerDelegate {
       mojom::WindowTreeRequest* tree_request,
       mojom::WindowTreeClientPtr* client) override;
   bool IsTestConfig() const override;
+  void OnWillCreateTreeForWindowManager(
+      bool automatically_create_display_roots) override;
 
  private:
   WindowServer* window_server_ = nullptr;
@@ -690,6 +692,32 @@ class WindowEventTargetingHelper {
 
 // -----------------------------------------------------------------------------
 
+class TestDisplayManagerObserver : public mojom::DisplayManagerObserver {
+ public:
+  TestDisplayManagerObserver();
+  ~TestDisplayManagerObserver() override;
+
+  mojom::DisplayManagerObserverPtr GetPtr();
+
+  std::string GetAndClearObserverCalls();
+
+ private:
+  std::string DisplayIdsToString(
+      const std::vector<mojom::WsDisplayPtr>& wm_displays);
+
+  // mojom::DisplayManagerObserver:
+  void OnDisplaysChanged(std::vector<mojom::WsDisplayPtr> displays,
+                         int64_t primary_display_id,
+                         int64_t internal_display_id) override;
+
+  mojo::Binding<mojom::DisplayManagerObserver> binding_;
+  std::string observer_calls_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestDisplayManagerObserver);
+};
+
+// -----------------------------------------------------------------------------
+
 // Adds a new WM to |window_server| for |user_id|. Creates
 // WindowManagerWindowTreeFactory and associated WindowTree for the WM.
 void AddWindowManager(WindowServer* window_server,