exo: Fix dragging edge cases

components/exo/shell_surface.h

Index: components/exo/shell_surface.h
diff --git a/components/exo/shell_surface.h b/components/exo/shell_surface.h
index e076537b91fbeb2a37cd764d5e4c90d898681646..8c242ec2e069f091754f9856ee716b6dba74f5d8 100644
--- a/components/exo/shell_surface.h
+++ b/components/exo/shell_surface.h
@@ -46,6 +46,7 @@ class ShellSurface : public SurfaceDelegate,
                      public ash::wm::WindowStateObserver,
                      public aura::WindowObserver,
                      public WMHelper::ActivationObserver,
+                     public WMHelper::ShellObserver,
                      public WMHelper::AccessibilityObserver {
  public:
   // The initial bounds are relative to the coordinate system from/to which the
@@ -237,6 +238,10 @@ class ShellSurface : public SurfaceDelegate,
       aura::Window* gained_active,
       aura::Window* lost_active) override;
 
+  // Overridden from WMHelper::ShellObserver:
+  void OnOverviewModeStarted() override;
+  void OnOverviewModeEnded() override;
+
   // Overridden from WMHelper::AccessibilityObserver:
   void OnAccessibilityModeChanged() override;
 
@@ -324,6 +329,7 @@ class ShellSurface : public SurfaceDelegate,
   StateChangedCallback state_changed_callback_;
   ConfigureCallback configure_callback_;
   ScopedConfigure* scoped_configure_ = nullptr;
+  bool ignore_widget_bounds_changes_ = false;
   bool ignore_window_bounds_changes_ = false;
   gfx::Point origin_;
   gfx::Vector2d pending_origin_offset_;