mash: Remove WorkspaceLayoutManagerDelegate.

ash/common/wm/workspace/workspace_layout_manager.h

Index: ash/common/wm/workspace/workspace_layout_manager.h
diff --git a/ash/common/wm/workspace/workspace_layout_manager.h b/ash/common/wm/workspace/workspace_layout_manager.h
index a91fc6156a892b3f2e40c87fe6284d7ca66805ca..e11a782ff8c59d526b3a6a4a449918d3f6b9e466 100644
--- a/ash/common/wm/workspace/workspace_layout_manager.h
+++ b/ash/common/wm/workspace/workspace_layout_manager.h
@@ -26,7 +26,6 @@ class WmRootWindowController;
 class WorkspaceLayoutManagerBackdropDelegate;
 
 namespace wm {
-class WorkspaceLayoutManagerDelegate;
 class WMEvent;
 }
 
@@ -40,14 +39,10 @@ class ASH_EXPORT WorkspaceLayoutManager
       public ShellObserver,
       public wm::WindowStateObserver {
  public:
-  WorkspaceLayoutManager(
-      WmWindow* window,
-      std::unique_ptr<wm::WorkspaceLayoutManagerDelegate> delegate);
-
+  // |window| is the container for this layout manager.
+  explicit WorkspaceLayoutManager(WmWindow* window);
   ~WorkspaceLayoutManager() override;
 
-  void DeleteDelegate();
-
   // A delegate which can be set to add a backdrop behind the top most visible
   // window. With the call the ownership of the delegate will be transferred to
   // the WorkspaceLayoutManager.
@@ -65,7 +60,6 @@ class ASH_EXPORT WorkspaceLayoutManager
 
   // WmRootWindowControllerObserver overrides:
   void OnWorkAreaChanged() override;
-  void OnFullscreenStateChanged(bool is_fullscreen) override;
 
   // Overriden from WmWindowObserver:
   void OnWindowTreeChanged(
@@ -91,12 +85,8 @@ class ASH_EXPORT WorkspaceLayoutManager
                                    wm::WindowStateType old_type) override;
 
   // ShellObserver overrides:
-  void OnFullscreenStateChanged(bool is_fullscreen, WmWindow* root) override {
-    // Do nothing. Fullscreen state change is observed by the
-    // WmRootWindowControllerObserver::OnFullscreenStateChanged().
-    // Because the name is conflicting, some compiler warns because this is
-    // hidden. To avoid it, we define it here, with empty body.
-  }
+  void OnFullscreenStateChanged(bool is_fullscreen,
+                                WmWindow* root_window) override;
   void OnPinnedStateChanged(WmWindow* pinned_window) override;
 
  private:
@@ -127,8 +117,6 @@ class ASH_EXPORT WorkspaceLayoutManager
   WmRootWindowController* root_window_controller_;
   WmShell* shell_;
 
-  std::unique_ptr<wm::WorkspaceLayoutManagerDelegate> delegate_;
-
   // Set of windows we're listening to.
   WindowSet windows_;