Tablet WM : 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..ca5ce8c597f9e06b40832943d1cdcc20d166b3bf 100644
--- a/ash/system/tray/system_tray.h
+++ b/ash/system/tray/system_tray.h
@@ -10,6 +10,7 @@
 #include <vector>

[tdanderson, 2017/06/19 16:19:38]

I see you are using bug 725977 to track many different changes. As a suggestion,
consider splitting each surface into its own bug, and mark these as blocking the
725977 tracking bug. In my opinion there are many advantages to doing this:

* It makes it easier to track what has already been done and what is left to do.
* If the feature work will span across different milestones, it's easier to tell
which parts were landed in which milestones since each bug will have its own M-
label.
* It is easier to track regressions, in case any individual CL needs to be
reverted.
* When a bug is used to track only a single piece of feature work, it makes it
simpler for the test team to perform manual verification.

[minch1, 2017/06/20 16:45:34]

Thanks for your suggestion Terry. I will split this issue into 
multiple small ones.

[tdanderson, 2017/06/20 22:42:20]

Acknowledged.

 
 #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,

[tdanderson, 2017/06/19 16:19:38]

Note that I have left a comment here listing the other overrides of
TrayBackgroundView:
https://bugs.chromium.org/p/chromium/issues/detail?id=725977#c4

It looks like you are planning to add "swipe up" functionality to many of these.
I'm OK with this as the first CL, but in a subsequent CLs consider opportunities
to move any common code into the TrayBackgroundView class.

[minch1, 2017/06/20 16:45:34]

Yes, I think it will has some code reuse in the following CLs after this feature
applied to some other parts.

[tdanderson, 2017/06/20 22:42:20]

Acknowledged.

-                              public views::TrayBubbleView::Delegate {
+                              public views::TrayBubbleView::Delegate,
+                              public ShellObserver {

[xdai1, 2017/06/19 19:01:30]

You don't need observe Shell to get the maximize mode state. It can always
calculated by
Shell::Get()->maximize_mode_controller()->IsMaximizeModeWindowManagerEnabled()

[minch1, 2017/06/20 16:45:34]

Done.

  public:
   explicit SystemTray(Shelf* shelf);
   ~SystemTray() override;
@@ -136,12 +138,23 @@ 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();
 
+  // Overridden from ui::EventHandler:

[tdanderson, 2017/06/19 16:19:38]

nit: just "ui::EventHandler:"

[minch1, 2017/06/20 16:45:34]

Done.

+  void OnGestureEvent(ui::GestureEvent* event) override;
+
+  gfx::Rect GetWorkAreaBoundsInScreen() const;
+
+  bool in_maximize_mode() { return in_maximize_mode_; }
+
  private:
   friend class SystemTrayTestApi;
   class ActivationObserver;
@@ -193,6 +206,42 @@ class ASH_EXPORT SystemTray : public TrayBackgroundView,
   // Overridden from ActionableView.
   bool PerformAction(const ui::Event& 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 IsDraggingDownOnShelf(const ui::GestureEvent& gesture);
+
+  // Update the bounds of the system tray bubble according to the location of
+  // the gesture drag.
+  void UpdateBoundsOnDragging(const ui::GestureEvent& gesture);
+
+  // Open the system tray bubble if the drag amount is larger than one third of
+  // the height of the bubble. Otherwise, close it.
+  bool ShouldShowSystemBubbleBasedOnDragAmount();
+
+  // Rules of opening / closing the system bubble for gesture dragging.
+  // |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 ShouldShowSystemBubbleForDragging(const ui::GestureEvent& gesture);
+
+  // Shelf the system tray is in.
+  Shelf* const shelf_;
+
+  // Swiping of the system tray bubble is only for maximize mode.

[tdanderson, 2017/06/19 16:19:38]

Can you clarify why you want to restrict this functionality to just maximize
mode? For consistency I would expect the same behavior to work when I am in
clamshell (non-maximized) mode with a touchscreen device. Removing the
restriction would also simplify your CL :)

[minch1, 2017/06/20 16:45:34]

I think the touch gestures here is only for tablet and horizontal shelf. Since
tablet will has horizontal shelf only in the future.

[tdanderson, 2017/06/20 22:42:20]

OK as discussed in the other email thread, in a follow-on CL please add user
actions metrics to track how often the swipe-up feature is used.

[minch1, 2017/06/22 17:42:10]

Done.

+  bool in_maximize_mode_ = false;
+
+  // The original bounds of the system tray bubble.
+  gfx::Rect system_tray_bubble_bounds_ = gfx::Rect();

[xdai1, 2017/06/19 19:01:30]

nit: I don't think you need this initialization. 

[minch1, 2017/06/20 16:45:34]

Done.

+
+  // Tracks the amount of the drag.
+  float gesture_drag_amount_ = 0.f;
+
   // The web notification tray view that appears adjacent to this view.
   WebNotificationTray* web_notification_tray_ = nullptr;