Wires up PointerWatcherEventRouter for views aura-mus

ui/aura/mus/window_tree_client.h

Index: ui/aura/mus/window_tree_client.h
diff --git a/ui/aura/mus/window_tree_client.h b/ui/aura/mus/window_tree_client.h
index c483e9386ab37d961b7930f37b39434b7b0ac9c8..991b49b99a4182bccd564bb388d48b6ee080b5b1 100644
--- a/ui/aura/mus/window_tree_client.h
+++ b/ui/aura/mus/window_tree_client.h
@@ -60,6 +60,10 @@ class WindowTreeClientObserver;
 class WindowTreeHost;
 class WindowTreeHostMus;
 
+namespace client {
+class CaptureClient;
+}
+
 using EventResultCallback = base::Callback<void(ui::mojom::EventResult)>;
 
 // Manages the connection with mus.
@@ -95,6 +99,8 @@ class AURA_EXPORT WindowTreeClient
   bool connected() const { return tree_ != nullptr; }
   ClientSpecificId client_id() const { return client_id_; }
 
+  client::CaptureClient* GetCaptureClient();
+
   void SetClientArea(Window* window,
                      const gfx::Insets& client_area,
                      const std::vector<gfx::Rect>& additional_client_areas);