Add DisplayCompositorTest.

services/ui/surfaces/display_compositor.h

Index: services/ui/surfaces/display_compositor.h
diff --git a/services/ui/surfaces/display_compositor.h b/services/ui/surfaces/display_compositor.h
index 94fa3f8f9078af8a30e79f4a207b5b48c3b70649..cec4a5f2115a6c482d4cd3a1043b1d2fc2f2aba7 100644
--- a/services/ui/surfaces/display_compositor.h
+++ b/services/ui/surfaces/display_compositor.h
@@ -7,6 +7,9 @@
 
 #include <stdint.h>
 
+#include <unordered_map>
+#include <vector>
+
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "cc/ipc/display_compositor.mojom.h"
@@ -22,8 +25,9 @@ class SurfaceManager;
 }  // namespace cc
 
 namespace ui {
-
-class DisplayCompositorClient;
+namespace test {
+class DisplayCompositorTest;
+}
 
 // The DisplayCompositor object is an object global to the Window Server app
 // that holds the SurfaceServer and allocates new Surfaces namespaces.
@@ -45,8 +49,15 @@ class DisplayCompositor : public cc::SurfaceObserver,
 
   cc::SurfaceManager* manager() { return &manager_; }
 
+  void set_reference_manager_for_testing(
+      cc::SurfaceReferenceManager* reference_manager) {
+    reference_manager_ = reference_manager;
+  }
+
  private:
   friend class base::RefCounted<DisplayCompositor>;
+  friend class test::DisplayCompositorTest;
+
   virtual ~DisplayCompositor();
 
   // cc::SurfaceObserver implementation.
@@ -58,6 +69,10 @@ class DisplayCompositor : public cc::SurfaceObserver,
 
   cc::mojom::DisplayCompositorClientPtr client_;
   cc::SurfaceManager manager_;
+  cc::SurfaceReferenceManager* reference_manager_;

[Fady Samuel, 2016/11/18 20:18:24]

Can we avoid having two references to the same thing? SurfaceManager is a
SurfaceReferenceManager?

[kylechar, 2016/11/24 20:43:14]

Not easily, at least from what I can think of. We need the whole SurfaceManager
public API available from DisplayCompositor. Making all of SurfaceManager into
an interface doesn't sound ideal just to write tests a bit easier.

Alternatively I could write code to generate
SurfaceFactories/Surfaces/SurfaceIds for tests so the real SurfaceManager is
used. Again, that isn't perfect and results in more complicated tests.

+
+  // Local copy of top level root surface id, for convenience.
+  const cc::SurfaceId root_surface_id_;
 
   // SurfaceIds that have temporary references from top level root so they
   // aren't GC'd before DisplayCompositorClient can add a real reference. This