[ash-md] Prevents auto-positioning after cancelling overview

ash/common/wm/overview/window_selector.cc

Index: ash/common/wm/overview/window_selector.cc
diff --git a/ash/common/wm/overview/window_selector.cc b/ash/common/wm/overview/window_selector.cc
index b24142b14492ce3febf825e12b5aea27378d7c57..c1464f308e431b4fdfa0ad85d6155520d4b4ab56 100644
--- a/ash/common/wm/overview/window_selector.cc
+++ b/ash/common/wm/overview/window_selector.cc
@@ -285,7 +285,8 @@ WindowSelector::WindowSelector(WindowSelectorDelegate* delegate)
       text_filter_string_length_(0),
       num_times_textfield_cleared_(0),
       restoring_minimized_windows_(false),
-      text_filter_bottom_(0) {
+      text_filter_bottom_(0),
+      shutting_down_(false) {
   DCHECK(delegate_);
 }
 
@@ -381,6 +382,7 @@ void WindowSelector::Init(const WindowList& windows) {
 // may cause other, unrelated classes, (ie PanelLayoutManager) to make indirect
 // calls to restoring_minimized_windows() on a partially destructed object.
 void WindowSelector::Shutdown() {
+  shutting_down_ = true;

[oshima, 2016/08/08 22:47:37]

can we just remove observer?

[varkha, 2016/08/08 23:45:35]

Yes, I considered this before but thought for some reason that we DCHECK on
repeated removal but we don't, at least not implicitly.
Done.

   size_t remaining_items = 0;
   for (std::unique_ptr<WindowGrid>& window_grid : grid_list_) {
     for (WindowSelectorItem* window_selector_item : window_grid->window_list())
@@ -553,12 +555,10 @@ void WindowSelector::OnDisplayRemoved(const display::Display& display) {
 
 void WindowSelector::OnDisplayMetricsChanged(const display::Display& display,
                                              uint32_t metrics) {
-  // If only the work area changes, there is no need to reposition windows in
-  // overview.
-  if (metrics != DISPLAY_METRIC_WORK_AREA) {
-    PositionWindows(/* animate */ false);
-    RepositionTextFilterOnDisplayMetricsChange();
-  }
+  if (shutting_down_)
+    return;
+  PositionWindows(/* animate */ false);
+  RepositionTextFilterOnDisplayMetricsChange();
 }
 
 void WindowSelector::OnWindowTreeChanged(WmWindow* window,