Implemented swipe to close in overview mode.

ash/wm/overview/window_selector_item.h

Index: ash/wm/overview/window_selector_item.h
diff --git a/ash/wm/overview/window_selector_item.h b/ash/wm/overview/window_selector_item.h
index 063b141e92a594c728efcd9633144251fd19bc28..0e4aa8fa1b83de29588c4e50fea66ca7d43068cb 100644
--- a/ash/wm/overview/window_selector_item.h
+++ b/ash/wm/overview/window_selector_item.h
@@ -33,18 +33,25 @@ class ASH_EXPORT WindowSelectorItem : public views::ButtonListener,
  public:
   class OverviewLabelButton : public views::LabelButton {
    public:
-    OverviewLabelButton(views::ButtonListener* listener,
+    OverviewLabelButton(WindowSelectorItem* selector_item,
                         const base::string16& text);
 
     ~OverviewLabelButton() override;
 
     void set_top_padding(int top_padding) { top_padding_ = top_padding; }
 
+    // views::LabelButton:
+    void OnGestureEvent(ui::GestureEvent* event) override;
+
    protected:
     // views::LabelButton:
     gfx::Rect GetChildAreaBounds() override;
 
    private:
+    // The WindowSelectorItem that the touch gestures are delegated to.
+    // Not owned.
+    WindowSelectorItem* selector_item_;
+
     // Padding on top of the button.
     int top_padding_;
 
@@ -94,6 +101,9 @@ class ASH_EXPORT WindowSelectorItem : public views::ButtonListener,
 
   const gfx::Rect& target_bounds() const { return target_bounds_; }
 
+  // Handles the gestures on the Window
+  void OnGestureEvent(ui::GestureEvent* event);
+
   // views::ButtonListener:
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
 
@@ -127,6 +137,14 @@ class ASH_EXPORT WindowSelectorItem : public views::ButtonListener,
   // Updates the close buttons accessibility name.
   void UpdateCloseButtonAccessibilityName();
 
+  // Animates the |transform_window_| back to it's original overview mode
+  // position.
+  void ResetScrolledWindow();
+
+  // Returns the minimum distance at which a scroll gesture will cause this
+  // selector item to be closed.
+  int GetMinimumCloseDistance() const;
+
   // True if the item is being shown in the overview, false if it's being
   // filtered.
   bool dimmed_;
@@ -158,6 +176,10 @@ class ASH_EXPORT WindowSelectorItem : public views::ButtonListener,
   // close_button_widget_.
   views::ImageButton* close_button_;
 
+  // The original X location for a scroll begin event. |original_x_| is in the
+  // local coordinate space of |window_label_button_view_|.
+  float scroll_x_origin_;
+
   DISALLOW_COPY_AND_ASSIGN(WindowSelectorItem);
 };