Makes it possible for clients to directly create WindowTreeHostMus

ui/aura/mus/window_tree_host_mus.h

Index: ui/aura/mus/window_tree_host_mus.h
diff --git a/ui/aura/mus/window_tree_host_mus.h b/ui/aura/mus/window_tree_host_mus.h
index 186fd30ae9a8aa11a6c1b605a45fe718c3a83572..0869b600515119919a03cd3ab95b4529775dea7b 100644
--- a/ui/aura/mus/window_tree_host_mus.h
+++ b/ui/aura/mus/window_tree_host_mus.h
@@ -11,7 +11,6 @@
 #include "services/service_manager/public/cpp/connector.h"
 #include "ui/aura/aura_export.h"
 #include "ui/aura/window_tree_host_platform.h"
-#include "ui/gfx/geometry/vector2d.h"
 
 class SkBitmap;
 
@@ -27,27 +26,15 @@ namespace aura {
 
 class InputMethodMus;
 class WindowPortMus;
+class WindowTreeClient;
 class WindowTreeHostMusDelegate;
 
-enum class RootWindowType;
-
-// WindowTreeHostMus is configured in two distinct modes:
-// . with a content window. In this case the content window is added as a child
-//   of the Window created by this class. Any changes to the size of the content
-//   window is propagated to its parent. Additionally once the content window is
-//   destroyed the WindowTreeHostMus is destroyed.
-// . without a content window.
-//
-// If a content window is supplied WindowTreeHostMus deletes itself when the
-// content window is destroyed. If no content window is supplied it is assumed
-// the WindowTreeHostMus is explicitly deleted.
 class AURA_EXPORT WindowTreeHostMus : public aura::WindowTreeHostPlatform {
  public:
   WindowTreeHostMus(std::unique_ptr<WindowPortMus> window_port,
                     WindowTreeHostMusDelegate* delegate,
-                    RootWindowType root_window_type,
-                    int64_t display_id,
-                    Window* content_window = nullptr);
+                    int64_t display_id);
+  explicit WindowTreeHostMus(WindowTreeClient* window_tree_client);
   ~WindowTreeHostMus() override;
 
   // Sets the bounds in dips.
@@ -57,56 +44,30 @@ class AURA_EXPORT WindowTreeHostMus : public aura::WindowTreeHostPlatform {
     return aura::WindowTreeHostPlatform::SendEventToProcessor(event);
   }
 
-  Window* content_window() { return content_window_; }
-
   InputMethodMus* input_method() { return input_method_.get(); }
 
-  // Offset of the bounds from its parent. The Window (and content window if
-  // present) always has an origin of 0x0 locally. This offset gives the offset
-  // of the window in its parent.
-  void set_origin_offset(const gfx::Vector2d& offset) {
-    origin_offset_ = offset;
-  }
-  const gfx::Vector2d& origin_offset() const { return origin_offset_; }
-
-  RootWindowType root_window_type() const { return root_window_type_; }
-
+  // Intended only for WindowTreeClient to call.
   void set_display_id(int64_t id) { display_id_ = id; }
+  int64_t display_id() const { return display_id_; }
   display::Display GetDisplay() const;
 
- private:
-  class ContentWindowObserver;
-
-  Window* GetWindowWithServerWindow();
-
-  // Called when various things happen to the content window.
-  void ContentWindowDestroyed();
-
   // aura::WindowTreeHostPlatform:
   void ShowImpl() override;
   void HideImpl() override;
   void SetBounds(const gfx::Rect& bounds) override;
-  gfx::Rect GetBounds() const override;
-  gfx::Point GetLocationOnNativeScreen() const override;
   void DispatchEvent(ui::Event* event) override;
   void OnClosed() override;
   void OnActivationChanged(bool active) override;
   void OnCloseRequest() override;
   gfx::ICCProfile GetICCProfileForCurrentDisplay() override;
 
+ private:
   int64_t display_id_;
-  const RootWindowType root_window_type_;
 
   WindowTreeHostMusDelegate* delegate_;
 
   bool in_set_bounds_from_server_ = false;
 
-  gfx::Vector2d origin_offset_;
-
-  // May be null, see class description.
-  Window* content_window_;
-
-  std::unique_ptr<ContentWindowObserver> content_window_observer_;
   std::unique_ptr<InputMethodMus> input_method_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTreeHostMus);