Removes WmRootWindowController subclasses

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index 86d2677f286c910c9d2db731e2ee68e7e8664e59..cf570f35a1ee2192d17e550f3bcf5b849022dcdb 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -26,6 +26,7 @@
 namespace aura {
 class RootWindow;
 class Window;
+class WindowTreeClient;
 namespace client {
 class ActivationClient;
 class FocusClient;
@@ -184,6 +185,15 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
   static const aura::Window* GetContainer(const aura::Window* root_window,
                                           int container_id);
 
+  // TODO(sky): better isolate this.

[James Cook, 2017/01/10 22:41:14]

Hrm. Yeah, this is kind of ugly. Could it live somewhere else? Maybe in
WmRootWindowController or RootWindowController? At least those are a bit less
visible than Shell.

[sky, 2017/01/10 23:06:57]

I put it in Shell as it isn't related to a single root (RootWindowController is
for a single root) and I suspect other places are going to need it.

+  static void set_window_tree_client(aura::WindowTreeClient* client) {
+    window_tree_client_ = client;
+  }
+
+  static aura::WindowTreeClient* window_tree_client() {
+    return window_tree_client_;
+  }
+
   // Creates a default views::NonClientFrameView for use by windows in the
   // Ash environment.
   views::NonClientFrameView* CreateDefaultNonClientFrameView(
@@ -414,6 +424,8 @@ class ASH_EXPORT Shell : public SystemModalContainerEventFilterDelegate,
 
   static Shell* instance_;
 
+  static aura::WindowTreeClient* window_tree_client_;

[James Cook, 2017/01/10 22:41:14]

Is this only set when running with mus? If so, please document that.

[sky, 2017/01/10 23:06:57]

Done.

+
   // If set before the Shell is initialized, the mouse cursor will be hidden
   // when the screen is initially created.
   static bool initially_hide_cursor_;