Exit overview mode when a new activity is opened in athena

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 4bb04501ff7acfe574fbfccb9318cd8dfdef771e..d818416954c18b605a864f8c9779e3703c6f7fcb 100644
--- a/athena/wm/window_manager_impl.cc
+++ b/athena/wm/window_manager_impl.cc
@@ -39,6 +39,9 @@ class WindowManagerImpl : public WindowManager,
     COMMAND_TOGGLE_OVERVIEW,
   };
 
+  // Sets whether overview mode is active.
+  void SetInOverview(bool active);
+
   void InstallAccelerators();
 
   // WindowManager:
@@ -101,6 +104,7 @@ WindowManagerImpl::WindowManagerImpl() {
 }
 
 WindowManagerImpl::~WindowManagerImpl() {
+  overview_.reset();
   if (container_) {
     container_->RemoveObserver(this);
     container_->RemovePreTargetHandler(bezel_controller_.get());
@@ -112,6 +116,7 @@ WindowManagerImpl::~WindowManagerImpl() {
 void WindowManagerImpl::Layout() {
   if (!container_)
     return;
+  SetInOverview(false);
   gfx::Rect bounds = gfx::Rect(container_->bounds().size());
   const aura::Window::Windows& children = container_->children();
   for (aura::Window::Windows::const_iterator iter = children.begin();
@@ -124,14 +129,22 @@ void WindowManagerImpl::Layout() {
 }
 
 void WindowManagerImpl::ToggleOverview() {
-  if (overview_) {
-    overview_.reset();
-    FOR_EACH_OBSERVER(WindowManagerObserver, observers_,
-                      OnOverviewModeExit());
-  } else {
+  SetInOverview(overview_.get() == NULL);
+}
+
+void WindowManagerImpl::SetInOverview(bool active) {
+  bool in_overview = !!overview_;
+  if (active == in_overview)
+    return;
+
+  if (active) {
     overview_ = WindowOverviewMode::Create(container_.get(), this);
     FOR_EACH_OBSERVER(WindowManagerObserver, observers_,
                       OnOverviewModeEnter());
+  } else {
+    overview_.reset();
+    FOR_EACH_OBSERVER(WindowManagerObserver, observers_,
+                      OnOverviewModeExit());
   }
 }
 
@@ -156,9 +169,7 @@ void WindowManagerImpl::OnSelectWindow(aura::Window* window) {
   CHECK_EQ(container_.get(), window->parent());
   container_->StackChildAtTop(window);
   wm::ActivateWindow(window);
-  overview_.reset();
-  FOR_EACH_OBSERVER(WindowManagerObserver, observers_,
-                    OnOverviewModeExit());
+  SetInOverview(false);
 }
 
 void WindowManagerImpl::OnWindowDestroying(aura::Window* window) {