athena: Allow getting into split-view mode from overview-mode.

athena/wm/window_manager_impl.cc

Index: athena/wm/window_manager_impl.cc
diff --git a/athena/wm/window_manager_impl.cc b/athena/wm/window_manager_impl.cc
index 47e49b64584e8948dc8408d24f1f17a7e993b4bd..5574905691e04ecd9a6f8e1c4d8b6f87a8e0d4b5 100644
--- a/athena/wm/window_manager_impl.cc
+++ b/athena/wm/window_manager_impl.cc
@@ -60,6 +60,8 @@ class WindowManagerImpl : public WindowManager,
 
   // WindowOverviewModeDelegate:
   virtual void OnSelectWindow(aura::Window* window) OVERRIDE;
+  virtual void OnSplitViewMode(aura::Window* left,
+                               aura::Window* right) OVERRIDE;
 
   // aura::WindowObserver
   virtual void OnWindowAdded(aura::Window* new_window) OVERRIDE;
@@ -212,6 +214,12 @@ void WindowManagerImpl::OnSelectWindow(aura::Window* window) {
   SetInOverview(false);
 }
 
+void WindowManagerImpl::OnSplitViewMode(aura::Window* left,
+                                        aura::Window* right) {
+  SetInOverview(false);
+  split_view_controller_->ActivateSplitMode(left, right);
+}
+
 void WindowManagerImpl::OnWindowAdded(aura::Window* new_window) {
   if (new_window->type() == ui::wm::WINDOW_TYPE_NORMAL)
     SetInOverview(false);