4 files changed, 26 insertions, 16 deletions

diff --git a/ui/aura/window.cc b/ui/aura/window.cc
index 86c9046..2c9aab8 100644
--- a/ui/aura/window.cc
+++ b/ui/aura/window.cc
@@ -235,6 +235,15 @@ Window::~Window() {
   if (host)
     host->dispatcher()->OnPostNotifiedWindowDestroying(this);
 
+  // The window should have already had its state cleaned up in
+  // WindowEventDispatcher::OnWindowHidden(), but there have been some crashes
+  // involving windows being destroyed without being hidden first. See
+  // crbug.com/342040. This should help us debug the issue. TODO(tdresser):
+  // remove this once we determine why we have windows that are destroyed
+  // without being hidden.
+  bool window_incorrectly_cleaned_up = CleanupGestureState();
+  CHECK(!window_incorrectly_cleaned_up);
+
   // Then destroy the children.
   RemoveOrDestroyChildren();
 
@@ -1324,6 +1333,19 @@ void Window::OnWindowBoundsChanged(const gfx::Rect& old_bounds) {
                     OnWindowBoundsChanged(this, old_bounds, bounds()));
 }
 
+bool Window::CleanupGestureState() {
+  bool state_modified = false;
+  state_modified |= ui::GestureRecognizer::Get()->CancelActiveTouches(this);
+  state_modified |=
+      ui::GestureRecognizer::Get()->CleanupStateForConsumer(this);
+  for (Window::Windows::iterator iter = children_.begin();
+       iter != children_.end();
+       ++iter) {
+    state_modified |= (*iter)->CleanupGestureState();
+  }
+  return state_modified;
+}
+
 void Window::OnPaintLayer(gfx::Canvas* canvas) {
   Paint(canvas);
 }
diff --git a/ui/aura/window.h b/ui/aura/window.h
index 2324533..6fbea36 100644
--- a/ui/aura/window.h
+++ b/ui/aura/window.h
@@ -326,6 +326,9 @@ class AURA_EXPORT Window : public ui::LayerDelegate,
   void PrintWindowHierarchy(int depth) const;
 #endif
 
+  // Returns true if there was state needing to be cleaned up.
+  bool CleanupGestureState();
+
  protected:
   // Deletes (or removes if not owned by parent) all child windows. Intended for
   // use from the destructor.
diff --git a/ui/aura/window_event_dispatcher.cc b/ui/aura/window_event_dispatcher.cc
index 5489596..36d8e6c 100644
--- a/ui/aura/window_event_dispatcher.cc
+++ b/ui/aura/window_event_dispatcher.cc
@@ -307,7 +307,7 @@ void WindowEventDispatcher::OnWindowHidden(Window* invisible,
   if (invisible->Contains(old_dispatch_target_))
     old_dispatch_target_ = NULL;
 
-  CleanupGestureState(invisible);
+  invisible->CleanupGestureState();
 
   // Do not clear the capture, and the |event_dispatch_target_| if the
   // window is moving across hosts, because the target itself is actually still
@@ -333,17 +333,6 @@ void WindowEventDispatcher::OnWindowHidden(Window* invisible,
   }
 }
 
-void WindowEventDispatcher::CleanupGestureState(Window* window) {
-  ui::GestureRecognizer::Get()->CancelActiveTouches(window);
-  ui::GestureRecognizer::Get()->CleanupStateForConsumer(window);
-  const Window::Windows& windows = window->children();
-  for (Window::Windows::const_iterator iter = windows.begin();
-      iter != windows.end();
-      ++iter) {
-    CleanupGestureState(*iter);
-  }
-}
-
 Window* WindowEventDispatcher::GetGestureTarget(ui::GestureEvent* event) {
   Window* target = NULL;
   if (!event->IsEndingEvent()) {
diff --git a/ui/aura/window_event_dispatcher.h b/ui/aura/window_event_dispatcher.h
index f0cb67f..6b476b7 100644
--- a/ui/aura/window_event_dispatcher.h
+++ b/ui/aura/window_event_dispatcher.h
@@ -162,10 +162,6 @@ class AURA_EXPORT WindowEventDispatcher : public ui::EventProcessor,
   // on capture (like DragDropTracker).
   void OnWindowHidden(Window* invisible, WindowHiddenReason reason);
 
-  // Cleans up the state of gestures for all windows in |window| (including
-  // |window| itself). This includes cancelling active touch points.
-  void CleanupGestureState(Window* window);
-
   // Returns a target window for the given gesture event.
   Window* GetGestureTarget(ui::GestureEvent* event);