[Test]Swiping on system tray bubble.

ash/system/tray/system_tray.h

Index: ash/system/tray/system_tray.h
diff --git a/ash/system/tray/system_tray.h b/ash/system/tray/system_tray.h
index fa16c53f74067aaee8e1eacaccff91add8d1d17d..1fc641c8fac1b69a4753ddac4fdf291d081eb399 100644
--- a/ash/system/tray/system_tray.h
+++ b/ash/system/tray/system_tray.h
@@ -10,6 +10,7 @@
 #include <vector>
 
 #include "ash/ash_export.h"
+#include "ash/shell_observer.h"
 #include "ash/system/tray/system_tray_bubble.h"
 #include "ash/system/tray/tray_background_view.h"
 #include "base/macros.h"
@@ -45,7 +46,8 @@ enum BubbleCreationType {
 };
 
 class ASH_EXPORT SystemTray : public TrayBackgroundView,
-                              public views::TrayBubbleView::Delegate {
+                              public views::TrayBubbleView::Delegate,
+                              public ShellObserver {
  public:
   explicit SystemTray(Shelf* shelf);
   ~SystemTray() override;
@@ -136,12 +138,20 @@ class ASH_EXPORT SystemTray : public TrayBackgroundView,
   base::string16 GetAccessibleNameForBubble() override;
   void HideBubble(const views::TrayBubbleView* bubble_view) override;
 
+  // ShellObserver:
+  void OnMaximizeModeStarted() override;
+  void OnMaximizeModeEnded() override;
+
   ScreenTrayItem* GetScreenShareItem() { return screen_share_tray_item_; }
   ScreenTrayItem* GetScreenCaptureItem() { return screen_capture_tray_item_; }
 
   // Activates the system tray bubble.
   void ActivateBubble();
 
+  gfx::Rect GetWorkAreaBoundsInScreen() const;
+
+  bool on_maximize_mode() { return on_maximize_mode_; }
+
  private:
   friend class SystemTrayTestApi;
   class ActivationObserver;
@@ -193,6 +203,39 @@ class ASH_EXPORT SystemTray : public TrayBackgroundView,
   // Overridden from ActionableView.
   bool PerformAction(const ui::Event& event) override;
 
+  // Overridden from ui::EventHandler:
+  void OnGestureEvent(ui::GestureEvent* event) override;
+
+  // Gesture related functions:
+  bool ProcessGestureEvent(const ui::GestureEvent& event);
+  bool StartGestureDrag(const ui::GestureEvent& gesture);
+  void UpdateGestureDrag(const ui::GestureEvent& gesture);
+  void CompleteGestureDrag(const ui::GestureEvent& gesture);
+
+  // Returns true if swiping down triggered on the system tray area on the
+  // shelf.
+  bool IsSwipingDownOnShelf(const ui::GestureEvent& gesture);
+
+  // Rules for showing / closing the system bubble for swiping.
+  // |ET_GESTURE_SCROLL_END| considers only the position of the dragging.
+  // |ET_SCROLL_FLING_START| should consider both position and velocity of the
+  // dragging.
+  bool ShouldShowSystemBubbleBasedOnPosition();
+  bool ShouldShowSystemBubbleForSwiping(const ui::GestureEvent& gesture);
+
+  Shelf* shelf_;
+  // Swiping of the system tray bubble is only for maximize mode.
+  bool on_maximize_mode_ = false;
+
+  // The original bounds of the system tray bubble.
+  gfx::Rect system_tray_bubble_bounds_;
+
+  // Tracks the amount of the drag.
+  float gesture_drag_amount_;
+
+  // Tracks the final scroll delta of the gesture event.
+  float final_scroll_y_;
+
   // The web notification tray view that appears adjacent to this view.
   WebNotificationTray* web_notification_tray_ = nullptr;