Handle modified displays in mustash.

ash/mus/root_window_controller.cc

Index: ash/mus/root_window_controller.cc
diff --git a/ash/mus/root_window_controller.cc b/ash/mus/root_window_controller.cc
index def83f68ac71d3476c037e94174445d704ddea0c..8642d5901dd4b8e9ae40fc575d231fd225686832 100644
--- a/ash/mus/root_window_controller.cc
+++ b/ash/mus/root_window_controller.cc
@@ -38,6 +38,7 @@
 #include "services/ui/public/cpp/window.h"
 #include "services/ui/public/cpp/window_property.h"
 #include "services/ui/public/cpp/window_tree_client.h"
+#include "services/ui/public/interfaces/display/display_controller.mojom.h"
 #include "ui/display/display_list.h"
 #include "ui/display/screen_base.h"
 
@@ -126,18 +127,21 @@ WmWindowMus* RootWindowController::GetWindowByShellWindowId(int id) {
 }
 
 void RootWindowController::SetWorkAreaInests(const gfx::Insets& insets) {
+  gfx::Rect old_work_area = display_.work_area();
   display_.UpdateWorkAreaFromInsets(insets);
+
+  if (old_work_area == display_.work_area())
+    return;
+
   display::DisplayList* display_list =
       window_manager_->screen()->display_list();
-  auto iter = display_list->FindDisplayById(display_.id());
-  DCHECK(iter != display_list->displays().end());
-  const display::DisplayList::Type display_type =
-      iter == display_list->GetPrimaryDisplayIterator()
-          ? display::DisplayList::Type::PRIMARY
-          : display::DisplayList::Type::NOT_PRIMARY;
-  display_list->UpdateDisplay(display_, display_type);
-  // TODO(kylechar): needs to push to DisplayController.
-  NOTIMPLEMENTED();
+  display_list->UpdateDisplay(display_);
+
+  // Push new display insets to service:ui.
+  display::mojom::DisplayControllerPtr display_controller;

[sky, 2016/10/19 23:37:59]

Can you make WindowManager maintain a single connection to display_controller.
Otherwise we may end up with subtle ordering issues when a bunch of stuff
changes.

[kylechar, 2016/10/20 15:04:19]

Done.

+  GetConnector()->ConnectToInterface("service:ui", &display_controller);
+  display_controller->SetDisplayWorkArea(display_.id(),
+                                         display_.bounds().size(), insets);
 }
 
 gfx::Rect RootWindowController::CalculateDefaultBounds(