Make it possible to change the viewport size

mojo/services/view_manager/connection_manager.cc

Index: mojo/services/view_manager/connection_manager.cc
diff --git a/mojo/services/view_manager/connection_manager.cc b/mojo/services/view_manager/connection_manager.cc
index 120e491f7dab36e4d01288a29d473798187ca516..36c1e4303ddd97dc3d14ecbfe5b41cea878481fd 100644
--- a/mojo/services/view_manager/connection_manager.cc
+++ b/mojo/services/view_manager/connection_manager.cc
@@ -6,6 +6,7 @@
 
 #include "base/logging.h"
 #include "base/stl_util.h"
+#include "mojo/converters/geometry/geometry_type_converters.h"
 #include "mojo/converters/input_events/input_events_type_converters.h"
 #include "mojo/public/cpp/application/application_connection.h"
 #include "mojo/public/interfaces/application/service_provider.mojom.h"
@@ -28,6 +29,10 @@ class WindowManagerInternalClientImpl
     real_client_->DispatchInputEventToView(transport_view_id, event.Pass());
   }
 
+  void SetViewportSize(SizePtr size) override {
+    real_client_->SetViewportSize(size.Pass());
+  }
+
   // InterfaceImpl:
   void OnConnectionError() override { error_handler_->OnConnectionError(); }
 
@@ -324,6 +329,11 @@ void ConnectionManager::OnViewPropertyChanged(
   }
 }
 
+void ConnectionManager::SetViewportSize(SizePtr size) {
+  gfx::Size new_size = size.To<gfx::Size>();
+  display_manager_.SetViewportSize(new_size);
+}
+
 void ConnectionManager::DispatchInputEventToView(Id transport_view_id,
                                                  EventPtr event) {
   const ViewId view_id(ViewIdFromTransportId(transport_view_id));